human domestication reconsidered - semantic …...human domestication reconsidered author(s): helen...

Human Domestication ReconsideredAuthor(s): Helen M. LeachSource: Current Anthropology, Vol. 44, No. 3 (June 2003), pp. 349-368Published by: The University of Chicago Press on behalf of Wenner-Gren Foundation for AnthropologicalResearchStable URL: http://www.jstor.org/stable/10.1086/368119 .

Accessed: 01/10/2013 05:41

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

The University of Chicago Press and Wenner-Gren Foundation for Anthropological Research are collaboratingwith JSTOR to digitize, preserve and extend access to Current Anthropology.

http://www.jstor.org

This content downloaded from 129.240.165.63 on Tue, 1 Oct 2013 05:41:03 AMAll use subject to JSTOR Terms and Conditions

http://www.jstor.org/action/showPublisher?publisherCode=ucpress

http://www.jstor.org/action/showPublisher?publisherCode=wennergren

http://www.jstor.org/action/showPublisher?publisherCode=wennergren

http://www.jstor.org/stable/10.1086/368119?origin=JSTOR-pdf

http://www.jstor.org/page/info/about/policies/terms.jsp


349

C u r r e n t A n t h ro p o l o g y Volume 44, Number 3, June 2003� 2003 by The Wenner-Gren Foundation for Anthropological Research. All rights reserved 0011-3204/2003/4403-0002$3.00

HumanDomesticationReconsidered1

by Helen M. Leach

In scientific usage, “domestication” has come to mean the pro-cess by which humans transformed wild animals and plants intomore useful products through control of their breeding. Certainphysical and behavioural changes have been identified as criteriaof domestication. They include morphological changes affectingthe skeletons of early Middle Eastern domesticates (e.g., reduc-tion in size and skeletal robusticity, cranio-facial shortening, anddeclining tooth size). These changes also occur in some humanpopulations starting in the Late Pleistocene. “Unconscious selec-tion” pressures are increasingly invoked in explanations of bothsets of data. The long-established paradigm of human controlover domestication through artificial selection has meant thatparallelism in these changes is seldom noted and few inclusiveexplanations have been attempted since the early 1900s. Re-cently, only symbolic and social domestication has been acceptedfor Homo sapiens. This article proposes a preliminary case forhuman biological domestication based on the effects of the builtenvironment, decreased mobility, and changes in diet consis-tency associated with increasing sedentism.

h e l e n m . l e a c h is Professor of Anthropology at the Univer-sity of Otago (P.O. Box 56, Dunedin, New Zealand [[email protected]]). Born in 1945, she was educated at theUniversity of Otago (B.A., 1966; M.A., 1969; Ph.D., 1976). Sheheld a Rhodes Fellowship at Oxford University in 1980–81 andhas done archaeological fieldwork in New Zealand and AmericanSamoa. Among her publications are 1,000 Years of Gardening inNew Zealand (Wellington: Reed, 1984), “Intensification in thePacific: A Critique of the Archaeological Criteria and Their Ap-plication” (current anthropology 40:311–39), and CultivatingMyths: Fiction, Fact, and Fiction in Garden History (Auckland:Godwit, 2000). The present paper was submitted 1 vii 02 and ac-cepted 7 x 02.

1. I thank my colleagues Nancy Tayles of the Department of Anat-omy and Structural Biology and Ian Smith of the Department ofAnthropology of the University of Otago for suggesting correctionsand clarifications. To Peter Wilson I am grateful for extended com-ments on the first draft, as well as for ideas and inspiration overthe many years we have shared an interest in Homo “domesticus.”Several anonymous referees provided many detailed criticisms thathave helped me shape the revised version.

In non-human mammals, the early history of domesti-cation is read from faunal assemblages from archaeolog-ical sites in the Middle East dated to the end of the Pleis-tocene and early Holocene eras. The state of domes-tication of individual animals is judged from morpho-logical changes in the skeleton, while the managementpractices implicated in the process of domestication areevaluated from the age and sex profiles of the speciesrepresented in each occupation or layer of the site. Sub-sequent effects of the domestication process can be rec-ognized where pictorial evidence depicts variations inbody shape and colouring and where texts describe be-havioural changes.

The study of domesticated animals since Darwin’s in-fluential work (1868) has culminated in the formationof a set of changes that are claimed to distinguish do-mestic populations from wild species (for recent outlinesof these see Price 1984, 1999; Hemmer 1990; Tchernovand Horwitz 1991; Hall 1993; Teichert 1993; Smith 1995;Zohary, Tchernov, and Horwitz 1998; Clutton-Brock1999; Trut 1999). Although not uniformly present in alldomesticated species, those affecting the skeleton mayinclude the following: (1) change in body size, initiallyto smaller, with decreasing skeletal robusticity; (2) re-duction in cranial capacity; (3) shortening of the facialregion of skull, including jaws, sometimes associatedwith tooth crowding and maleruption and/or reductionin size of cheek teeth; (4) reduction in sexual dimor-phism; and (5) greater diversity in shape and size of horns(in cattle, sheep, and goats). Domestication changes af-fecting only soft tissues, body biochemistry, and/or be-haviour and therefore archaeologically invisible in anydirect form may include the following: (6) increasing var-iation in coat colour and hair structure; (7) increasing fatstorage (subcutaneous and intramuscular); (8) enhancedphysiological performance, including lactation; (9) pre-cocity, extended breeding seasons, and greater sexualstimulation; (10) retention of juvenile behaviours intoadulthood; (11) greater litter size and frequency of mul-tiple births; (12) reduction in motor activity; (13) reduc-tion in information acquisition systems; (14) reductionin intraspecific aggression, especially in males (thoughthis may be attenuated defensive behaviour); and (15)increased docility as part of reduced environmental re-sponsiveness.

The effects of domestication on the domestic animalresult from combinations of inherited genetic changesand the individual’s reactions to its environment in thecourse of development (its ecophenotypic responses). Inits broadest sense that environment starts with the nu-trient supply to the foetus and after birth involves boththe maternal input and the conditions under which theanimal lives. Availability of food and water, shelter fromclimatic extremes, protection from predators, levels ofexercise, population density, and social structure all con-stitute environmental factors that not only affect theindividual phenotype but through selection can influ-ence evolutionary adaptations in descendants. Selectionin the context of domestication includes the relaxationof natural selection pressures that operated in the wild



350 F current anthropology Volume 44, Number 3, June 2003

(e.g., when wild predators are eradicated) or the changedoperation of natural pressures in modified environments(e.g., overheating in close confinement or exposure tocold through removal of shelter). It can also involve theimposition of new selection pressures. Conscious or ar-tificial selection (as in deliberate breeding for a precon-ceived result) may be the most conspicuous of these, butunconscious selection, which covers the ground betweenartificial selection and natural selection, can also occurin combination with genetic drift and inbreeding. Un-conscious or involuntary selection may favour traits thatare prerequisites to those that are the object of consciousselection or may reduce the frequency of traits that com-pete with desired features for energy or space (Jacksonand Diamond 1996:1649). Heterochronic changes (i.e.,shifts in the rate or timing of ancestral developmentalpatterns [see Shea 1989:70]) produced in the course ofartificial selection for certain behaviours can also leadto unintended by-products as a result of developmentalconstraints.

The non-genetic effects of domestication occur be-cause of the plasticity shown by the individual pheno-type, particularly in response to diet and biomechanicalloadings during growth. These effects are produced afreshin each generation exposed to the same conditions andnot passed on genetically. Researchers have not yet iden-tified precisely how many of the so-called criteria of do-mestication are genetically encoded and how many areecophenotypic. In many cases both factors will interactto affect the phenotype, for it is now widely recognizedthat genes and environment do not operate independent-ly (Price 1999:247).

The changes outlined above which are manifest skel-etally are not, however, exclusive to domestic animals.During the late Pleistocene similar skeletal trends appearin certain groups of modern humans and expand duringthe Holocene until nearly all humans share them.Though similar, they have not been accepted as evidencethat modern humans have in some fashion become phys-ically domesticated. As will be argued below, the reasonsfor this lie in the boundaries historically erected aroundthe concept of domestication. Before these are reviewed,however, it is necessary to compare the morphologicalchanges observed in humans in the late Pleistocene andHolocene with those listed as criteria of domesticationin animals to determine whether they are indeed thesame phenomena despite the sometimes divergent ex-planations offered for their appearance.

Morphological Changes in Humans and inEarly Domesticated Mammals

Of the five skeletally visible criteria, horn morphologyis inapplicable, and therefore four require consideration.The categories under which these criteria are examinedby archaeozoologists are not a precise match to thoseused by paleoanthropologists. For convenience of dis-cussion, post-cranial robusticity will be dealt with first

and changes in cranio-facial proportions, cranial robus-ticity, dentition, and cranial capacity later. Sexual di-morphism will not be discussed separately. Although re-duction in sexual size dimorphism is predicted fromcomparisons of wild sheep and goats with domesticbreeds (Zohary, Tchernov, and Horwitz 1998:132) and hasbeen the subject of debate in studies of Late Palaeo-lithic–Mesolithic human populations (e.g., Frayer 1980,Collier 1993), calculation of the degree of dimorphismis dependent on carefully controlled data sets involvingsize dimensions. As will be shown below, size is deter-mined by both genetic and environmental factors. Sinceassessment of sexual dimorphism requires size compar-isons between adults which for this analysis have to besexed on features other than size, interpretation prob-lems are multiplied. A decrease in sexual dimorphismcan follow from relaxation of selection for large size inmales (Frayer 1980), poor nutrition and infection affect-ing an entire group (Goodman et al. 1984:20–21), betteraccess to protein by females (Rose et al. 1984:408), andchanges in the division of labour (Bridges 1989).

changes in body size, stature, and post-cranial robusticity

Since the 1960s, many prehistorians and archaeozoolo-gists have used smaller body size in early domestic an-imals relative to the wild species as a major criterion ofdomestication. It is generally determined from a varietyof measures of the particular limb and head elementsthat survive in archaeological sites (e.g., distal breadthsof humeri, metacarpals, and metatarsals, proximalbreadths of phalanges, and mandibular and tooth dimen-sions [Reitz and Wing 1999]).

The causes and mechanisms of size reduction havebeen the subject of considerable speculation (e.g., Jarmanand Wilkinson 1972, Meadow 1989). For cattle, CarolineGrigson (1969:287) favoured isolation of breeding units(restricting gene flow) coupled with selection by humansfor manageable size and the phenotypic effects of poorstock-keeping. Barbara Bender (1975:44) attributed sizereduction in cattle to malnutrition, noting a considerabledecrease in bone density accompanying this decline. Intheir review of the literature, Tchernov and Horwitz(1991:56), following Grigson (1969:281), pointed out that,while the phenomenon can occur without any humaninvolvement (as when populations of medium-sized tolarge animals undergo dwarfism following isolation onislands and when temperatures rise as they did at theonset of the Holocene), size change in primeval domes-ticates is localized and relatively greater than any changein contemporary wild populations (p. 56). Among theexplanations they reviewed were conscious selection forsmaller, docile, more easily handled, earlier-maturing an-imals, which require less food, unconscious selection foranimals which survive nutritional stress and disease, andremoval of the selection pressure imposed by predatorson smaller animals. They further proposed (p. 57; see alsoTchernov and Valla 1997:90) that as body size respondedto human-modified habitats, unconscious selection fa-



leach Human Domestication Reconsidered F 351

voured higher reproductive rates (r-selection) over indi-vidual viability (K-selection). While Tchernov and Hor-witz’s emphasis was on changes in selection pressuresaffecting the genotype, Smith (1995:32) put forward arange of nutrition-related causes which would operatephenotypically to stunt the development of the individ-ual: poorer nutrition status in pregnant females affectingthe foetus, earlier weaning, and higher parasite loads incaptivity. Similarly, Teichert (1993:235) attributed smallsize in domesticated bovines and pigs to poor juvenileand sub-adult nutrition.

More recently, size reduction in sheep and goats, nowjoined with decline in skeletal robusticity, has beenlinked to additional selection pressures (Zohary, Tcher-nov, and Horwitz 1998). Zohary, Tchernov, and Horwitzhave proposed that, in addition to the relaxation of nat-ural selection by predation, the breakdown of the alpha-male dominance pattern in mating relaxed selectionpressure for both large body size and horn size in males.They have also suggested that reduced skeletal robus-ticity in both sexes is a result of the relaxation of selec-tion pressures “maintaining adaptive traits for exploi-tation of rugged terrain (goat) or hilly terrain (sheep)”and that reduced body size is linked to increased com-petition under impoverished conditions (p. 132).

In a direct challenge to the validity of the size-reduc-tion phenomenon in the early domesticated goat assem-blage from Ganj Dareh, Melinda Zeder (2001) has arguedthat the evidence reflects changes in sex ratios of adults,poorer survival of bone from culled sub-adult males, andmethodological biases. Nevertheless, she concedes thatgoats in the later Ali Kosh site were smaller. Possibleexplanations are “selective factors that favour smalleranimals in managed herds,” “harsher environmentalconditions,” and domestication from a wild populationof smaller goats (Zeder 2001:77). She concludes that sizeis influenced by too many factors to be used as a markerof the first stages of domestication. Whether or not herviews are sustained by future analyses of caprine re-mains, size reduction has been well documented in pigsand cattle and, even more significant, in dogs. For Na-tufian dogs buried with humans, Tchernov and Valla(1997:88–89) have demonstrated not only decrease inoverall size relative to wolves but disproportionate re-duction in certain limb dimensions that they attributeto “reduced mobility” in these early commensals. Foranimals, then, reduction in overall body size and robus-ticity in the early stages of domestication is explainedby most commentators in terms of a mixture of geneticand ecophenotypic mechanisms involving the relaxationof natural selection pressures operating in nature, theaction of natural selection pressures in the captive set-ting, and the imposition of new, largely unconsciouspressures. These follow to a significant extent from theprovision of protection, the culling of young males, re-ductions in movement, and changes in diet. Artificialselection for smaller size is less commonly invoked.

With the exception of the culling of young males (un-less we invoke warfare as the human equivalent), sed-entary village life similarly offered protection to human

populations, discouraged high mobility, and affected dietbreadth. To what extent are changes in size evident inhuman populations, and how have they been tradition-ally explained?

Though the term “size” is commonly used by archaeo-zoologists, in biological anthropology its use is more fre-quent in analyses of living humans than in those of pre-historic remains. In growth studies of modern peoples,“size” is a portmanteau term combining height, weight,and certain other measures that contrasts with “shape,”the distribution of mass and body part proportions (e.g.,Eveleth and Tanner 1990). When comparing prehistorichuman samples, paleoanthropologists work with mea-sures of long bone length and various formulae for con-verting them to estimates of stature. For present pur-poses, stature in humans is the variable closest to sizeas recorded for prehistoric animals.

Physical anthropologists have long been aware of con-siderable changes in stature in anatomically modern hu-mans in the late Pleistocene but have found it difficultto decide whether to attribute them to gene flow frommigration or the genetic effects of isolation and inbreed-ing (Wells 1963:375). Similar stature decline has beennoted in skeletal remains from sites chronologicallyclose to the transition to food production. Although notuniversally observed, such instances of stature reductionhave occurred in such widely scattered regions of theNew and Old Worlds that the phenomenon has beencausally linked to the adoption of agriculture (Cohen andArmelagos 1984, Cohen 1989). Speculation about thecontributing factors has extended beyond the effects ofgene flow and gene drift to include the effects of stresson the individual skeleton. There is less consensus, how-ever, about the mechanisms involved.

Some of the contributors to Cohen and Armelagos’s(1984) volume Paleopathology at the Origins of Agri-culture specifically acknowledged the genetic compo-nent in human height (Goodman et al. 1984:19; Buikstra1984:222; Cook 1984:237; Dickel, Schulz, and McHenry1984:448; Roosevelt 1984:571, 573) but regarded this asa factor to be controlled for by excluding, for example,stature comparisons between an immigrant populationand a group it displaced. If continuity in genetic markerswas evident and major gene flow ruled out, then staturereduction in adults and delayed or reduced growth in sub-adults was attributed to physiological disruption orstress (Goodman et al. 1984:19). Angel (1984:59–60) spec-ulated that the decline in stature in some Eastern Med-iterranean Mesolithic people (compared with tall UpperPalaeolithic specimens) was due to “new endemic dis-eases causing anemias . . . or local decline in calories.”Meiklejohn et al. (1984:90) found the dietary-stress ex-planation for decrease in average stature in Western Eu-rope from the Upper Palaeolithic to the Neolithic to becomplicated by differing trends in males and females.Rathbun (1984:143) noted a slight decrease in the Iran-Iraq region from the pre-agricultural stage to the Neo-lithic, “consistent with adjustments to a different eco-nomic base,” but considered adult stature “a fairly poorindicator of nutritional status.” For South Asia, a trend




to reduced stature with the onset of food production wastentatively linked to both diet quality and reduction insexual dimorphism (Kennedy 1984:174). Several of theAmerican studies in this volume used declines in adultand sub-adult statures and bone lengths to documentchanges in both nutritional status and disease load (e.g.,Cook 1984:240; Larsen 1984:376, 382). This associationof diet and disease in explanations of stature reductionwas implicit in the instructions to the contributors tocompare the health status of the prehistoric human pop-ulation “before, during, and after the Neolithic Revo-lution” (Cohen and Armelagos 1984:xix).

Studies of growth and physique in living populationsprovide strong support for a physiological-stress modelof growth retardation and reduced adult size (Eveleth andTanner 1990:241, 243), but they also identify other fac-tors less frequently considered by prehistorians. The tim-ing of stress has been found to be critical in relation tothe likelihood of compensatory growth. Clark SpencerLarsen (1995:191) believes that this catch-up mechanismmight conceal dietary stress in prehistoric cases whereno change in adult stature is detected. At the same timeas chronic mal- or undernutrition has been found to actsynergistically with infection, modern population stud-ies have demonstrated that climate, social class, andeven psychological stress can be correlated with growthand attained height (Eveleth and Tanner 1990:224, 248–49, 260).

Climate, in its role as a selection pressure operatingon genetic variations, has long figured in debates overPleistocene stature trends. In contrast to populations in-volved in the transition to agriculture, the 20,000-yeartime scale of Upper Palaeolithic fossils in Europe en-courages such evolutionary interpretations. In their dis-cussion of stature decline from the Early Upper Palaeo-lithic to the Mesolithic, Vincenzo Formicola and MonicaGiannecchini (1999:321) treat stature as “a geneticallydetermined trait with a large environmental component. . . a sensitive tool for inferring life conditions and mi-croevolutionary trends.” They report that the greatestreduction (ca. 10 cm) followed the Last Glacial Maxi-mum at 18,000 b.p. but continued into the Mesolithic.Dismissing selective burial of tall individuals in theEarly Upper Palaeolithic and climatic selection pressures(which should have affected the tropically adapted ana-tomically modern humans long before 18,000 b.p.), theyexplain stature decline in terms of a combination of nu-tritional stress and the isolation of breeding units as ter-ritories shrank with a deteriorating European climate(Formicola and Giannecchini 1999:326–28, cf. Holliday1999:562).

Body size changes have thus been widely documentedin animals and humans at the close of the Pleistoceneand during the transition to agriculture. In locationswhere these events coincide, interpretation is compli-cated by the fact that a warming or cooling climate canitself precipitate stature or size change. Many animalspecies show a negative correlation between size andenvironmental temperature. In vertebrate mammals (ex-cluding humans), a warming climate can initiate overall

size reduction, as Simon Davis (1981) documented forthe fox, wolf, wild boar, aurochs, gazelle, and wild goatin the Levant at the end of the Pleistocene (ca. 12,000b.p.). For the first animals to become domesticated in theFertile Crescent, increasingly early dates for herd man-agement are squeezing the period of domestication upagainst the onset of Holocene warming, making it muchharder to distinguish climate-induced size reductionfrom that associated with domestication. In humans,however, stature can increase with temperature as limbsegments lengthen to increase cooling capacity (Holliday1999:552)—unless, as is proposed for the Pygmy phy-sique, humidity is so high that sweating is ineffective(Holliday and Falsetti 1995:149–50). But the human stat-ure decline in Late Upper Palaeolithic Europe and Mes-olithic Europe does not comfortably fit this model—itseems too late to be a response to the cold Europeanclimate which anatomically modern H. sapiens encoun-tered on moving out of the Near East ca. 40,000 b.p., andstature does not rebound with the warmer temperaturesof the Holocene until the past few centuries (Floud,Wachter, and Gregory 1990:24). This suggests that wherea decline occurs it is responding to a cultural transfor-mation, as is convincingly argued for Latin America byBogin and Keep (1999).

Given the range of causes invoked to explain size re-duction, it is significant that many of the factors invokedfor domestic animals are mirrored in the literature onhuman stature reduction, especially those involving nu-tritional and environmental stress on the individual, ge-netic selection for smaller individuals with lower foodneeds, and the isolation of breeding units. Yet while thetrends in animals are widely accepted as evidence of do-mestication, for humans this is not viewed as an option.

Robusticity in humans requires separate considera-tion. In animals skeletal robusticity is linked to sizechange. Many of the measurements used to study do-mestication effects in goats, sheep, and cattle (Reitz andWing 1999) are anatomically equivalent to those whichin humans contribute not to estimates of stature but toindices of epiphyseal robusticity (Pearson 2000:576). Inhumans robusticity is now broken down into cranial andpost-cranial manifestations, with vigorous debate overthe factors influencing the latter (Pearson 2000). Tradi-tional measures of diaphyseal robusticity have used mid-shaft dimensions over length, while those of epiphysealrobusticity utilize head diameters or epicondylar widths/breadths over length. These “relative thickness for size”assessments of limb elements have been applied tochronologically diverse skeletal remains from australo-pithecines to recent Homo. For researchers of hominidevolution, the resulting ratios or indices quantify generalimpressions of robust or gracile body forms. For pre-sap-iens fossils, robusticity is portrayed as a largely genetictrait, with an overlay of sexual dimorphism. For homi-nids of the Upper Pleistocene, however, there has beenincreasing recognition of the role of lifestyle factors op-erating epigenetically on the post-cranial skeleton. Stud-ies of bone strength in modern humans have revealedthe extent to which bone shafts and articulations re-




spond to body mass, shape, and physical activity (Ruff2000:270). Unravelling the allometric components ofchanging post-cranial robusticity is a major task but onethat must precede explanations involving changes in life-style and technology (Trinkaus, Churchill, and Ruff1994). Diaphyseal robusticity is considered more respon-sive to an individual’s activity levels than articular ro-busticity (Ruff et al. 1993:21; Lieberman, Devlin, andPearson 2001:273–76), and therefore declines in dia-physeal dimensions and changes in cross-sectional ge-ometry have become the subject of debates centred onsubsistence activities.

Several contributors to Cohen and Armelagos’s (1984)volume on the transition to agriculture treated femoraland tibial shape changes from flattened to rounded shaftcross sections as a marker of reduced physical demandson agriculturalists (Perzigian, Tench, and Braun 1984:352; Larsen 1984:376, 381). Subsequent studies, however,have identified some groups in which bone diaphyseshave become thicker on the transition to agriculture,implying greater workloads (Bridges 1989:391; Jacobs1993:316–17). Jackes, Lubell, and Meiklejohn (1997:649–50) attributed changes in diaphyseal shape in theirPortuguese sample to the influence of terrain as well asto general activity levels, and Larsen (1995:201–3) hassingled out a decline in mobility and long-distance travelas a factor additional to changing workloads. These ex-planations parallel those offered for loss of general skel-etal robusticity in domestic sheep and goats consequenton territorial confinement and removal from a ruggedenvironment.

Ultimately the long-term Pleistocene–Holocene de-cline in human diaphyseal robusticity has been linkedto increasing relative brain size, a greater reliance ontechnology, and more sedentism (Ruff et al. 1993:21, 47).Pearson (2000) has recently argued that climate shouldbe seen as even more significant, claiming that both ep-iphyseal and diaphyseal robusticity indices respond tothe greater body mass (relative to stature) that charac-terizes cold-adapted populations. What has been missedin the ensuing debate is the link between sedentism andclimate whereby the built environment of the sedentarygroup modifies the microclimate experienced by itsoccupants.

changes in cranial and dental features

Declining cranial robusticity in domesticated animals isusually discussed in connection with changes in hornmorphology or cranio-facial reduction (e.g., Zeuner 1963:68). Deliberate selection has been suggested for thepolled condition, especially in cattle, to make animalhandling less dangerous to humans and to other animals.However, evidence of decreasing cranial thickness con-comitant with horn changes in sheep and goats is inter-preted by Zohary, Tchernov, and Horwitz (1998:132) tomean that selection for strong horns and robust skullswas relaxed when human interference reduced alphamales’ head-on battles for dominance and access tobreeding females. This implies some measure of segre-

gation of the dominant males. Thus unconscious arti-ficial selection operating through the removal of a nat-ural selection pressure may well have precededdeliberate selection for hornlessness. Both explanationsimply strong genetic influence on cranial robusticity.Cranial vault thickness also responds to the stimulus ofexercise (Lieberman 1996). When two groups of siblingpigs were raised, one subject to an exercise regime, theother to pen confinement, the exercised pigs developedsignificantly greater cranial vault thickness, as well asgreater cortical area and linear limb-bone dimensions(pp. 224–25). The differences in robusticity appeared tobe systemically induced, possibly through the stimula-tion of growth hormone secretion by exercise (p. 230).

Cranial robusticity in humans has attracted muchgreater attention, though without widespread agreementas to what the term should include. As Pearson (2000:601) has pointed out, the word “robust” can be appliedto “crania that have large superstructures such as brow-ridges, mastoid processes, and nuchal crests, crania thathave rugged muscle markings, or crania that have someunspecified combination of these features.” A trend tosmoother, more gracile crania is a well-documentedthough not universal phenomenon from the end of thePleistocene to the present (Lahr 1996:315; Kennedy 1984:174; Martin et al. 1984:202). Reductions in robusticityover time were documented from Natufian samples(Smith, Bar-Yosef, and Sillen 1984:111), although by com-parison with some contemporary groups Natufians hadrelatively gracile crania (Lahr and Wright 1996:181).

Marta Lahr and Richard Wright have made a signifi-cant contribution to current understanding of cranial ro-busticity in concluding that gracility is a derived com-plex in recent human populations rather than an initialcharacteristic of anatomically modern H. sapiens andthat the component elements of robusticity (such as largesupraorbital ridges, large zygomaxillary tuberosities, de-veloped zygomatic trigones, deep infraglabellar notches,and pronounced occipital tori) are linked as parts of asingle functional complex correlated with cranial size(Lahr and Wright 1996:160, 187; Lahr 1996:249). In Lahr’sopinion, mechanical stress mediated by genetically in-fluenced skull dimensions affects the degree of devel-opment of these robust superstructures (1996:183–84).The question of the extent to which robusticity in Pa-tagonian and Australian Aboriginals is retained from thelate Pleistocene, when robusticity was the norm for hu-mans (Lahr and Wright 1996:160; Lahr 1996:24, 248), ora derived modern feature responding to a demanding life-style and environment (Hernandez, Lalueza Fox, andGarcia-Moro 1997) cannot be resolved without furtherdated samples. To Lahr, the argument that technologicaldevelopments in the Upper Palaeolithic removed the se-lection pressure for robusticity, especially in males(Frayer 1980:409), is unconvincing because recenthunter-gatherers have such variable levels of robustic-ity—for example, San and Inuit are more gracile thanPatagonian and Australian Aboriginals (Lahr 1996:263).While Lahr sees a strong genetic basis for cranial di-mensions, Lieberman (1996:228, 231) links the 20–30%




loss in one of those dimensions, cranial vault thickness,with changing subsistence strategies.

Along with cranial robusticity, human cranial size re-duction is noticeable in many post-Pleistocene popula-tions. Lahr (1996:24) found that in cranial dimensionshumans associated with the Upper Palaeolithic Aurig-nacian culture were 10–30% larger than more recentgracile humans. However, there was little size reductionin groups that retained (or reacquired) robust skull fea-tures, such as the Patagonians, whose crania were 10%larger than those of recent non-robust samples (Lahr1996:222). This does not necessarily mean that endo-cranial capacity fell, because cranial height commonlyincreased as gracilization occurred (p. 246). The much-repeated argument that Neandertals had even larger cra-nial capacity than the modern humans who followedthem in Europe now has to be seen in the light of theallometric effect of increased body mass. According toRuff, Trinkaus, and Holliday (1997) and Wolpoff (1999:767), once body mass has been factored out Neandertalbrain mass was slightly smaller. A worldwide decreasein human brain size in the Holocene documented byMaciej Henneberg (1997:6) has similarly been linked todecreasing body size. In John Kappelman’s (1996:273)view, no general trend can be detected in human cranialcapacity since the appearance of anatomically modernH. sapiens 100,000 years ago brought an increase in rel-ative brain size and a decrease in body mass.

Despite these views, John Allman (1999) likens humanbrain size reduction to that which occurred when wolveswere domesticated. Relative to size, dogs lost 30% oftheir brain size under domestication, and Allman attrib-utes this to human provision of food and shelter. He thensuggests by analogy that “humans, through the inven-tion of agriculture and other cultural means for reducingthe hazards of existence, have domesticated themselves”(Allman 1999:206–7). This statement ignores the actualwording of the cited reference (Ruff, Trinkaus, and Hol-liday 1997:175)—that it was absolute brain size that de-clined in parallel with average body size.

Among domestic animals, however, evidence has beenaccumulating since the 1950s for disproportionate brainsize reduction relative to the size of the body, as well asdifferential shrinkage of centres of sensual perceptioncompared with wild species (Zeuner 1963:72; Kruska1987, 1996). For the pig, up to 33.6% brain weight re-duction has been documented by Rohrs and Ebinger(1999). For horses, Rohrs and Ebinger (1998) found thatdomesticated specimens had about 14% less braincasecapacity and 16% less brain weight than wild Przewalskihorses, while samples of the latter kept in zoos sharedthe same reduction as domestic horses. Kruska (1987:64)outlined relative brain size decreases of 30% from dogto wolf and from ferret to polecat. Time since domesti-cation was not a consistent factor, for brain size in theranch mink has declined by nearly 20% (independent ofbody size, sex, and age) in only 120 generations since thedomestication process began (Kruska 1996:646, 654). Do-mestic animals that have become feral do not return tothe brain weights of the wild species (Kruska 1987:65;

Rohrs and Ebinger 1998), an observation consistent withHerre and Rohrs’s (1977:252) earlier conclusion that suchbrain size reduction is “hereditary.” The mechanism ofbrain weight loss is increasingly discussed as individualbrain structures are separately measured. Sensory sys-tems and structures regulating attentiveness and aggres-sion show significant declines in pigs, sheep, ranchmink, and dog (Kruska 1996:659). It is likely that con-finement of certain domestic animals in cages, pens, andstables has led to a higher degree of loss than in morefree-ranging animals—provided, of course, that the con-fined populations do not interbreed with the extensivelyreared animals.

Though human cranial capacity does not show a sim-ilar disproportionate decline, perhaps because humanshave enjoyed much greater freedom and stimulation,many Holocene populations share a complex of cranio-facial and dental changes with domestic animals, espe-cially dogs and pigs. Despite the morphological parallels,the explanations are rather divergent. Cranio-facialshortening in the dog was considered by Juliet Clutton-Brock (1963, 1969) to precipitate tooth crowding and dis-placement followed by reduction in the size and com-plexity of the teeth, particularly the canines andcarnassials. The initial trigger was then believed to bean overall reduction in body size, which shortened themuzzle without a corresponding reduction in its width(Clutton-Brock 1963:21). Frederick Zeuner (1963:67) ob-served that as a general rule “the facial part of the skulltends to be shortened relative to the cranial” and thatthe tendency, “which incidentally is present in manalso,” occurs very conspicuously in the pig, severalbreeds of dog, and the domestic cat and, less conspicu-ously, cattle, sheep, and goats. Hemmer (1990:24–25) in-voked positive allometry to explain how as animal sizedecreased the muzzle diminished, leaving the braincasedominant, but he also pointed out that specific short-muzzled forms such as the pug dog and the Persian cathad been deliberately bred, “independent of the allo-metric change in muzzle length due to size” (p. 26). Therelated concepts of neoteny, raised initially by Zeuner,and paedomorphosis were woven into later explanations(e.g., Clutton-Brock 1999:36; Tchernov and Valla 1997:85, 92). While both terms refer to heterochronic retentionof juvenile characters into adulthood (Shea 1989:70–72;Churchill 1998:48), neoteny in its pure form is a partic-ular type of paedomorphosis in which allometric pat-terns are dissociated and retarded without changing adultsize or duration of growth (Shea 1989:72). In Natufiandogs it was the anterior portion of the muzzle that short-ened relative to the posterior, suggesting a neotenicchange. However, body size declined significantly, whichis more indicative of hypomorphosis. Coupled with sometooth size reduction but no loss of muzzle breadth, thechange was classed as paedomorphic and linked to over-all body size reduction, along with relaxed selection pres-sure for effective hunting. A softer diet was proposed toexplain more slender mandibular ramus dimensions(Tchernov and Valla 1997:79, 86).

In Belyaev and Trut’s silver-fox domestication exper-




iment, however, cranial height and width diminishedand snouts became shorter and wider without overalldecrease in body size (Trut 1999:167). Over this 40-yearproject, in which the foxes were confined to cages, rig-orous selection specifically for tame and against aggres-sive behaviour was accompanied by these unexpectedmorphological changes. The investigators believe thatthe genes involved in the chemical regulation of thesebehaviours through the adrenal cortex and the serotoninsystem had other ontogenetic roles (Trut 1999:166). Sig-nificant changes in the endocrine systems of domesticguinea pigs compared with the wild cavies also show upas less intraspecific aggression coupled with more court-ship behaviour and less attention to the physical envi-ronment (Kunzl and Sachser 1999:35–36). The relativeimportance of active selection for certain behaviours andunconscious selection for animals that breed success-fully under close confinement remains to be established.

In contrast, the cranio-facial shortening documentedin recent Homo has usually been linked to dietaryrather than heterochronic change. David Carlson’s(1976) influential study of 10,000 years of cranio-facialevolution in Lower Nubia identified a reduction in themassiveness of the muscles involved in chewing as theprimary stimulus. These trends were attributed tochanges in diet as the Nubians moved from hunter-gatherer subsistence to increasingly intensive agricul-ture (Carlson 1976:279, 294–95). Teeth were also af-fected, becoming smaller and less complex over thesame period. Martin et al. (1984:203) proposed thatsmaller and simpler teeth would be selected for as beingless prone to the carious lesions associated with a soft,sticky, high-carbohydrate (millet) diet. At the sametime, a reduction in the attrition rate removed the se-lection pressure for large teeth and their supportingmusculature. The removal of this pressure as a resultof technological innovation in cooking was a key ele-ment in C. Loring Brace’s (1978) explanation of cranio-facial and dental change in Asian populations. In her1978 study of the Mesolithic burials at Vlasac, Yugo-slavia, Gloria y’Edynak identified changes in jaw sizeand dentition as biomechanical and genetic responsesto new tools and food preparation and storage tech-niques that reduced masticatory stress and jaw size,creating selection pressures for smaller teeth withfewer cusps that operated through the mechanism ofperiodontal disease in individuals with crowded and ro-tated teeth (pp. 616–17).

Since the 1950s, tooth size reductions, with or with-out tooth crowding and tooth rotation, have been con-sidered significant markers of the early stages of do-mestication in dogs and pigs (Clutton-Brock 1963, 1969,1999; Davis and Valla 1978; Hole, Flannery, and Neely1969:313; Tchernov and Horwitz 1991; Tchernov andValla 1997:80), but until recently there has been no ex-tension of diet- or technology-related hypotheses fromhuman case studies to studies of domestic animals. Inan experiment with Yucatan minipigs, Ciochon, Nis-bett, and Corruccini (1997) induced malocclusions andsignificant differences in cranial dimensions in those

fed a soft diet compared with those fed identical nu-trients in a hard form. Much earlier experiments on pigsreported by Darwin (1868, vol. 1:72) had concluded that“rich and abundant food, given during youth, tends bysome direct action to make the head broader andshorter.” These experiments confirmed observations inhuman populations that malocclusions can develop inthe space of a single generation in groups undergoingurbanization and adopting a “Westernized” diet. If hu-man malocclusion is stimulated by the adoption of asoft diet, did Neolithic dogs share both the diet and thedental consequences with their “masters”?

The plasticity of the cranium, which is significantlyaffected by chewing forces (Lahr 1996:182–83; Spencerand Ungar 2000:238–39), can be contrasted with the sta-bility of the teeth (Larsen 1995:192). Because they areformed so early in life they are often used to study ge-netic differences between human groups and trends inhominid evolution. In the case of dental agenesis, geneticcontrol is unquestionable; however, tooth size respondsto both genetic and ecophenotypic factors, especially ma-ternal health status and foetal nutrition (Larsen 1995:192–93). Human tooth-size reduction since the Palaeo-lithic has been widely documented (Kieser 1990:51). Aswith cranio-facial reduction, both natural selection forsmall teeth and reduced natural selection for large teethhave been invoked. Indeed, many of the theories addressboth phyletic shortening of the maxillofacial complexand tooth-size reduction within the one scenario.

To sum up, at the end of the Pleistocene, certain hu-man groups and their animal associates began progres-sively to show parallel reductions in size and stature,cranial gracilization, changes in post-cranial robusticity,shortening of the face and jaws, tooth crowding and mal-occlusion, and tooth-size reduction and simplification.There has been no recent attempt to explain the par-allelism, although numerous explanations exist for thechanges as they affect one or other of the parties. Someof the explanations are the same—such as response toHolocene warming, allometric and heterochronic effects,isolation of breeding units, reduction in activity levels,and diet quality—while others reflect the traditional di-vision between the domesticated animal and the humandriver. Thus for animals explanations may be couchedas the effects of deliberate breeding, poor herd manage-ment, protection from predators, sensory deprivation, orculling. For humans the same morphological changesmay be attributed to technological improvements,changing subsistence strategies, or greater intelligence.Very few post-1950 researchers apart from Zeuner havenoted the parallels in these morphological trends, andnone have commented on the differences in the expla-nations. Increasingly, however, selection pressures thatdid not involve intentional breeding are being proposedfor animals, overlapping with those in the literature onhuman evolutionary change.

The above review of the changes and hypothesizedcauses has revealed just how uncertain biologists andanthropologists are about the relative contributions ofgenetic and ecophenotypic factors. Despite this, some




quite elaborate scenarios have been developed. Viewedin retrospect, some read like just-so stories reflecting pre-vailing paradigms of research and debate. There has beena marked failure to seek overarching explanations for thechanges or absence of changes in all the species involved.It can only be assumed that paleo- and physical anthro-pologists had no interest in the morphological changesoccurring in certain domestic animals because they werethe result of human selection, while archaeozoologistsignored morphological changes in humans precisely be-cause humans were not domesticates.

Defining “Domestication”

The history of the terminology of “domestication”throws considerable light on scholarly reluctance to en-tertain the notion of human domestication in other thana social or an ideological sense. While it is true thathumans have been described as sharing domesticationtraits with their animals, the schools of thought asso-ciated with such claims are no longer highly regarded.Theodosius Dobzhansky summed up prevailing opinionin 1962 with the comment, “In fact, ‘domestication’ ofman is too vague an idea to be scientifically productive”(1962:196). In the early 17th century, however, the word“domesticate” was applied only to humans, in the senseof civilizing or becoming part of a household (OxfordEnglish Dictionary, 2d edition). From the end of the 18thcentury animals were included; the use of the term inrelation to plants was uncommon until the second halfof the 20th century. By the 1970s, its scientific appli-cation was to a process driven by humans and culmi-nating in the modification of certain plants and animalspecies for human benefit.

application of the term to animals

As the heyday of “natural history,” the 19th century sawsustained enquiry into the relationship of humans andanimals. Not surprisingly, “domestication” came tomean more than the taming of individual creatures, hav-ing been extended beyond the process of accustominganimals to human proximity to incorporate human con-trol. Charles Darwin used the concept throughout hiswriting, and his 1868 work The Variation of Animalsand Plants under Domestication focused on the role ofmethodical selection. His interest in the topic ensuredthe continuation of “domestication” as the term ofchoice for referring to the transformation of animalsfrom wild species to recognized breeds.

For V. Gordon Childe (1928:2) domestication providedone of the great moments in prehistory, “that revolutionwhereby man ceased to be purely parasitic and, with theadoption of agriculture and stock-raising, became a cre-ator emancipated from the whims of his environment.”Although he saw the desiccation-induced concentrationof animals and humans in oases and along river banksas promoting “symbiosis,” the outcome of their inter-action was far from symbiotic: men became “masters of

their own food supply” (p. 42). Nearly 70 years later “cre-ation” was an element of Bruce Smith’s recent startingdefinition of domestication as “the human creation of anew form of plant or animal—one that is identifiablydifferent from its wild ancestors and extant wild rela-tives” (1995:18).

Human mastery was also inherent in Juliet Clutton-Brock’s (1992:41) oft-quoted definition of a domestic an-imal as “bred in captivity, for purposes of subsistence orprofit, in a human community that controls its breeding,its organisation of territory, and its food supply.” For theanimals there are both biological and social effects, in-cluding genetic changes and incorporation into the socialstructure of a human community, while for humans theanimals can become like artefacts, “the objects of own-ership, inheritance, purchase, and exchange” (Clutton-Brock 1999:30–32). Helmut Hemmer’s definition of a do-mestic animal had essentially the same core: an animal“kept and bred in and around human habitation to beused constantly to human advantage” (1990:1). Accord-ing to Hemmer, the taming of individual wild animalsor the breeding of them in captivity does not constitutedomestication because they are not subject to selectionfor a particular human use. Similarly, creatures that co-habit with humans as unwelcome guests “also havenothing to do with domestication”; their adaptation tohumans is best described as commensalism (pp. 1, 178).

As 20th-century definitions became increasingly de-tailed and circumscribed in order to accommodate grow-ing knowledge of the traits which distinguish domesticanimals from wild ones, anomalous cases emerged ofanimals, such as sparrows and mice, whose relationshipswith humans fall outside useful subservience but meetsome of the distinguishing criteria. The easiest resolu-tion of the dilemma they constituted was to classifythem as not “domesticated” but “commensal.”

the objects of unconscious selection

The adoption of the ecosystem paradigm by prehistoriansfrom the 1960s was accompanied by an increasing rec-ognition of the importance of unconscious selection.This concept, too, has undergone a change in meaning.Darwin (1868, vol. 1:214) regarded unintentional or un-conscious selection as breeding driven by the simple de-sire to maintain good stock. Methodical or consciousselection saw the breeder seeking to preserve a new anddesirable variation or “to create some improvement al-ready pictured in his mind.” Though Sandor Bokonyi(1989:26) adheres to Darwin’s usage, to some 20th-cen-tury writers unconscious selection was more akin to nat-ural selection but operating within a human-modifiedenvironment. Eitan Tchernov and Liora Kolska Horwitz(1991:57) revived Heiser’s definition of unconscious se-lection as “resulting from human activities not involvinga deliberate attempt to change the organism.” More re-cently Zohary, Tchernov, and Horwitz (1998:129) havedescribed unconscious selection as that type of selectionbrought about by placing plants and animals “in a new(and quite different) human-made environment. This




shift in the ecology led automatically to drastic changesin selection pressures.” Adaptations which enhancedsurvival in the wild were no longer maintained by nat-ural selection, while variation produced new traits thatwere automatically selected for if they fitted the systemof agriculture or husbandry to which they were exposed.Eventually these built up into a range of “domesticationsyndromes.” Thus the human role in unconscious se-lection was now perceived as potentially no more thanthe creation of a modified environment, and early farm-ers were portrayed as unaware of many of the changestaking place in the crops and herds.

Rindos’s (1984) reinterpretation of domestication (fo-cused on plants) as a form of coevolution had even greaterpotential to undermine the standard anthropocentric def-initions of domestication. Subsequently T. P. O’Connor(1997:149) presented a strong case for the weakness ofcurrent definitions of animal domestication as appliedto the early phases of the process. He found them to becentred on a few Middle Eastern species of caprines andargued that the wild:domestic dichotomy does not ade-quately describe the differing relationships that exist be-tween humans and their close animal associates (p. 151).Furthermore, biologists apply the terms “mutualism”and “commensalism” to many interactions between an-imal (including insect) species that are comparable tothose between humans and their domesticates. In fact,O’Connor considered these biological terms preferablefor describing the early coevolutionary stages of humanrelationships with animals that preceded conscious se-lective breeding.

O’Connor (1997:151, 154) pointed to the cases of thehouse sparrow (Passer domesticus) and the house mouse(Mus musculus subspecies). Abandoning the term “do-mestication” for species that have not been altered byconscious selection has had an important effect on ourunderstanding of how such species emerged. WhereasHemmer’s (1990:178–79) definition of domestication hadmarginalized these species as commensals, O’Connormoved several traditional domesticates into the com-mensal category. Thus sparrows and mice, which havesorely tested traditional definitions of domestication,have now been removed from their anomalous positionand reexamined.

It is necessary to explain how the house mouse (ex-cluding the selectively bred laboratory mouse) and thehouse sparrow acquired some of the morphologicalchanges listed as criteria of domestication when they areneither useful to humans nor controlled by them. Spe-cifically, four subspecies of M. musculus have adaptedto commensalism with humans, developing changes inpelage, longer tails, shortening of the face and molar row,and possible reduction in size according to the closenessof their association (Tchernov 1984:93). Initially, Tcher-nov identified M. musculus in Mousterian sites in theLevant; however, Boursot et al. (1993:130) have tracedM. musculus to the Indian subcontinent and argued thatbefore the Epipalaeolithic the only mouse in the Levantwas the wild M. macedonicus, which did not become acommensal with humans. The subspecies of M. mus-

culus which developed some “traits of domestication”seem to have done so in several independent centres; oneof them, M. musculus domesticus, spread through theFertile Crescent in association with human sedentismbeginning in the Epipalaeolithic (Boursot et al. 1993:130).On the Iberian peninsula, a commensal M. musculussubspecies arrived at the same time as donkeys andchickens in the Iron Age. It was distinguishable from thelocal wild mouse M. spretus by its smaller size (MoralesMunız et al. 1995:131, 133). Boursot et al. (1993:136)stress that agriculture was not the key factor in the dis-persal of M. m. domesticus. In the Middle East thismouse was associated with pre-Neolithic human dwell-ings, while its appearance in western Europe was linkedto increasing post-Neolithic sea traffic. The provision ofa suitable artificial habitat seems to be the key factor inthe evolution and spread of house mice.

The house sparrow may have developed in the MiddleEast from a “pre-domestic” form (Tchernov 1984:95,107). It penetrated northern Europe only in the lateBronze Age, in association with the horse. Both shelter(as in stables) and a winter feed supply would have beenneeded for its survival there. In its spread westwardthrough the Mediterranean basin it came into contactwith the closely related wild Passer hispaniolensis, theSpanish sparrow, and formed stable hybrid populationswith it in Italy and Crete (Ericson et al. 1997:186). Mor-phological changes suggested for P. domesticus conse-quent on commensalism with humans or, more pre-cisely, with human stock animals involve a decrease insize (Morales Munız et al. 1995:129–30), particularly inthe skeletal parts involved in food processing and ter-restrial movement, compared with the wild P. hispan-iolensis.

If this evidence of morphological change is sustainedin further studies, then the cases of the house mouse andthe house sparrow indicate that commensal species, notsubject to conscious selection or even control by hu-mans, have responded to selection pressures or ecophen-otypic factors connected with the artificial environmentof built structures and stored foods that typified the earlyvillage, whether or not it was supported by agriculture(Tchernov 1993:191). If the involuntary selection of cer-tain traits was an outcome of plants’ and animals’ livingin the human-made environment, is it not possible thata variety of domestication traits (or even a distinctivesyndrome) may have built up in humans, who sharedthat environment?

humans as domesticates

Once the word “domesticate” became associated withanimal breeding, occasional reference was made to hu-mans’ “domesticating themselves,” adopting the animalusage for particular effect (e.g., Bagehot’s [1905:51] ar-gument that self-domestication led to civilization). Twomore recent books deliberately stretched the concept ofdomestication to explore human societal change fromthe end of the Palaeolithic. Peter Wilson’s The Domes-tication of the Human Species (1988) identified a range




of social changes that occurred in most cases concur-rently with the adoption of the built environment, in-cluding a new emphasis on boundaries, the division ofspace into public and private, gendered domains, theemergence of the neighbour and of instruments for socialcontrol, and significant modifications in the capacity forattention (pp. 4–5, 29–32, 57–61, 104–7). Ian Hodder’sThe Domestication of Europe: Structure and Contin-gency in Neolithic Societies (1990) maintained that so-cial and symbolic domestication may have preceded ec-onomic domestication. For Hodder, the significant socialunit in the transformation, the household, was inti-mately connected to the domus (house, including its ser-vice facilities). This provided both a structural and con-ceptual locus for the activities that domesticated itshuman, plant, and animal inhabitants (pp. 31–34).Though he accepted that morphological change occurredin the plants and animals, Hodder did not explore thepossibility that domestication of humans extended be-yond the social and symbolic domains.

Remarkably, this was first attempted at the end of the19th century by a number of German anthropologistsand further developed by Franz Boas in the early 1900s.Boas’s writings on human domestication were influ-enced in part by his analyses of changes of body formamong the children of European migrants to America(Stocking 1968:176–80). The degree of skeletal plasticitythat he encountered cast considerable doubt on the pre-vailing idea of fixed human types, or “races.” He wasalready aware of some general trends in recent humanevolution, such as the tendency of teeth to decrease insize, and of Gustav Fritsch’s findings in South Africa ofbone-density differences between Bushmen and Hotten-tots and Europeans. Fritsch had observed similar differ-ences in the skeletons of wild and domesticated animalsand, in Boas’s words (1938:77), concluded that “the Bush-men are in their physical habitus to a certain extent likewild animals, while the Europeans resemble in theirstructure domesticated animals.” But Boas believed thatall types of human had undergone changes linked to do-mestication and cited the works of Johannes Ranke, Eu-gen Fischer, and Eduard Hahn in support of this belief(Boas 1938:84 n. 1).

Three types of morphological change needed to be dis-tinguished. Boas (1938:77) spelled these out in relationto domestic animals: transformations resulting from“the change in nutrition and use of the body” (i.e., eco-phenotypic), from selection, and from what he termed“crossing” (both genetic). He discussed changes broughtabout by “more regular and more ample nutrition,” by“a new diet imposed by man,” and by different ways inwhich “the muscular and the nervous systems are putinto use.” He distinguished between carnivores and her-bivores and among the latter between those fed on pas-tures and those kept in stables “under highly artificialconditions.” In the earliest domestic animals he consid-ered only unconscious selection to have contributed tomodifications in form. It was not until artificial selectionand isolation of breeds were consciously practised thatthe markedly different forms of domesticated animals

emerged (pp. 78–79). Turning to humans, he found themost active influences to have been change in mode oflife and the effects of “crossing.” No humans still atelike wild animals or relied simply on brute strength incombat. Cookery, he argued, was universal and had af-fected the demands made on the digestive system forsome 50,000 years. The cooking of food had initiated theprocess of domestication in humans, along with the useof clothes that provided “artificial means of protectionagainst climate.” Together with weapons and other tools,these modified both individual development and chancesof survival.

Pursuing the analogy between domesticated animalsand human “races” further, Boas identified the followingshared transformations: increased melanism and leucism(marked loss of pigment), shortening or lengthening ofthe muzzle/face, hair crinkling, the development of ex-cessively long hair, and great variation in stature. Func-tional changes in milk-secreting structures and “anom-alies of sexual behavior” were also picked out (1938:83–85). But Boas could not reach a consistent positionon environmental and hereditary influences, and the dis-continuities in his conclusions prevented widespreadrecognition of his contribution (Stocking 1968:185). Mis-use and abuse of biometrics by the eugenics movementand “scientific” support of racist policies to the point ofcondoning genocide resulted in the virtual disappearanceof this theory of human domestication from post-1950anthropological writings. In ethology, however, Fischer’sideas influenced Konrad Lorenz in the 1940s and ’50sand his pupil Irenaus Eibl-Eibesfeldt (1970). Emphasizingshared behavioural changes as much as morphologicalsigns, they warned of the physical and moral dangersposed to humans by “domestication-induced deficien-cies” (Eibl-Eibesfeldt 1970:197; Lorenz 1971:236–37).Retrospectively, Boas deserves more credit for recogniz-ing the effects on both animals and humans of artificialmeans of protection against the extremes of weather,cultural changes in food availability and form, and re-duced activity levels. In the light of new evidence fromarchaeozoology and biological anthropology, it is appro-priate to reconsider the concept of human domestication.

Rethinking the Criteria of Domestication

Despite mainstream acceptance of the criteria of do-mestication, doubts have been raised since the 1960sover whether they are exclusively associated with do-mestication and whether any of the traits are “generallydiagnostic” (Berry 1969:207, 214). Berry’s concerns werefurther developed by Michael Jarman and Paul Wilkin-son (1972:96), who argued that some of the changes“were undoubtedly the product of human agencies, butit is more difficult than has generally been acknowledgedto distinguish between these and the results of otherevolutionary mechanisms.” This statement remainstrue—as the present review reveals, imperfect under-standing of the mechanisms responsible for the mor-




phological changes makes it difficult to evaluate thecompeting scenarios.

Over 30 years later we find not only the same criteriaof domestication but the suggestion explored here thatanother species, modern H. sapiens, displays them. Thenumber of skeletal structures that demonstrate changesand the number of species that share the changes are aconvincing argument against coincidental, independentdevelopment. But is the term “domestication” still vi-able if human morphological changes are included?Should the criteria be assigned to other phenomena? Ifthe definition of domestication requires that humans“drive” the process, as “masters” and “creators” of do-mestic breeds for human advantage, then the only do-mestication event involving humans as objects that canbe accommodated by this definition is slavery (cf. Clut-ton-Brock 1992:43). Similarly, if our definition of do-mestication requires it to be the product of consciousartificial selection, then only morphological changes pro-duced by a eugenic breeding programme could charac-terize human “domesticates.” We would then be left, forexample, with one set of explanations for cranio-facialand tooth-size reduction in early Epipalaeolithic and Ne-olithic dogs and pigs and another for humans—that is,the status quo.

But morphological changes observed in various ani-mals, both recent and ancient domesticates, are increas-ingly ascribed to unconscious selection. As this reviewhas shown, changes brought about by unconscious se-lection can include (1) unintentional by-products of de-liberate selection by humans, (2) the results of naturalselection operating in a human-modified environment,(3) variations permitted by the relaxation of natural se-lection pressures, and (4) the outcomes of new selectionpressures that are brought about by humans but of whichthey are largely unaware. While the first requires theexistence of artificial breeding intentions, the remainingthree cannot be ruled out in explanations of human mor-phological changes. For example, catastrophic natural se-lection events such as the mud flows and dust stormsthat can follow repeated vegetation clearance affect hu-man and animal survival alike. Technologies that reducethe mortality of weaklings and diseases that emerge indensely crowded settlements similarly influence bothhuman and animal genetic fitness. When morphologicalchanges are not genetic but environmentally induced,they can be expected to occur in many of the speciesvoluntarily or involuntarily sharing that new environ-ment.

If it is accepted that the criteria of domestication en-compass more than the products (and by-products) ofconscious selection, then the possibility of human do-mestication must be reconsidered, and researchers in bi-ological anthropology, archaeozoology, and animal be-haviour would do well to share their findings on themechanisms (genetic, epigenetic, and ecophenotypic)which underpin them. Though the term “domestica-tion” is not universally acceptable, it does serve to drawattention to the potential role of the built environment

and other cultural constructions in bringing about suchmorphological changes in humans and animals.

Even if it is set aside because of its historical associ-ations, the changes that have been bundled together asmarkers of the onset of new human-animal relations stilldeserve individual reconsideration in the light of recentresearch. How much cranio-facial reduction is a heter-ochronic response to selection for non-aggressive behav-iour and how much is produced by a softer diet? To whatextent does body and skull size decline under the lessextreme weather conditions of Holocene warming or asresult of more substantial housing or in response to poornutrition? Though it would be unreasonable to expectone overarching explanation for these phenomena, at thevery least we should ask why one explanation shouldnot be tested for closely similar changes in two symbioticanimals.

At this stage I favour retention of the term “domes-tication” for heuristic reasons. By viewing domesticationin its broadest sense as acclimatization to life in a house-hold and extending that concept to incorporate the houseand its outbuildings, yards, gardens, and orchards (as inHodder’s [1990] domus), we can reconsider some of thecriteria of domestication as biological changes broughtabout through living in this culturally modified, artificialenvironment. In such a reconsideration it will be nec-essary to account for the chronological spread of the mor-phological trends. In humans and dogs they start in someareas of Eurasia in the Late Pleistocene and precede sim-ilar changes in the majority of early domestic animals,in particular in goats, sheep, pigs, and cattle. We willneed to consider what changes in the Near Eastern en-vironment and lifestyle mark the Epipalaeolithic period,when the morphological changes become apparent inboth humans and dogs. Can they still be linked to theprovision of an artifical environment? In this pre-Neo-lithic era, diet was composed of a broader spectrum ofplants and animals and stone technologies diversifiedinto composite tools often based on microliths and dis-tinctive projectile points (Bar-Yosef and Meadow 1995).Grinding and pounding equipment became common-place. Stone vessels were made and storage bins con-structed from slabs or plastered hollows. Houses werebuilt with solid foundations and partly sunken floors andapparently occupied for prolonged periods of the year. Ofall these developments, the most intimately sharedamong humans, dogs, and sparrows were likely to havebeen the buildings and the foodstuffs. The complex ofhouses and yards protected all the settlement’s inhabi-tants in the winter months, including invited and un-invited commensals. As titbits, scraps, or spoiled items,foods prepared from pounded and ground plant partsreached the dogs and, later in the Neolithic era, the pigskept in the household compounds. A shared diet betweenhumans, dogs, and pigs—one that was becoming softerin consistency—might partly explain the shared gracil-ization and cranio-facial and dental reduction in thesespecies.

What environmental conditions did humans have incommon with sheep, goats, and cattle that might ac-




count for shared reductions in size/stature and post-cra-nial robusticity? An extension of the climate-change hy-pothesis provides a possible explanation. If herds werecorralled overnight in sheltered areas in or near villagessuch as in caves, wadis, tree groves, or abandoned houses,the biological effect on the individual animal might havebeen comparable to a climatic amelioration of severaldegrees. The sharing of sheltered domestic space insidethe household would have affected dogs and pigs in sim-ilar fashion. Did the domestic microclimate relax selec-tion for metabolic, insulative, or hypothermic adapta-tions to cold (Bittel 1992) in increasingly sedentaryhumans, thereby committing them to cultural adapta-tions for the management of cold? As human mobility,both logistic and residential (Holliday and Falsetti 1995:149–50), declined in the early Neolithic period, activitylevels of the domestic herd animals might be expectedto have followed. They no longer needed to flee the ap-proaching human or carnivore predator, and their feedingrange became confined to the territory controlled by thehousehold or the village.

If one factor were to be identified as a prerequisite, itwould be sedentism, the habit of “settling down” in onelocation for longer periods than was possible for mostforaging societies. This made the effort of house con-struction worthwhile, permitted the elaboration ofplant-processing equipment and the diversification ofcooking methods, allowed food to be accumulated ingrain stores, and reduced the distances travelled dailyand the loads carried by human groups. Sedentism pre-ceded the visible signs of plant and animal domestica-tion, and semisedentism came even earlier. Significantly,some of the European Mesolithic populations displayingthe morphological changes have been described as semi-or “relatively” sedentary (Vlasac, Serbia [y’Edynak 1978:616; 1989:23], eastern Mediterranean [Angel 1984:60],Portugal [Jackes, Lubell, and Meiklejohn 1997:651–52],northern Europe [Meiklejohn et al. 1984:78; Meiklejohnand Zvelebil 1991:133]). Perhaps the least mobile of allpre-Neolithic populations yet studied, the Natufians hadalready experienced stature reduction, some graciliza-tion, and tooth-size reduction (Smith, Bar-Yosef, and Sil-len 1984:110–11; Lahr 1996:83, 215–16) before cereal do-mestication is evident. By shifting the explanations forthe morphological trends from the transition to agricul-ture, as explored by Cohen and Armelagos (1984), to theadoption of the built environment and changes in foodtechnology, the chronological strain inherent in the for-mer argument is removed.

A key factor in this human-domestication hypothesisis the artificial protective environment created by hu-mans and shared progressively with animals and plants.It contributed to an increase and consequent concentra-tion of their numbers and to conscious or unconsciousinterference in breeding. For the human, the combina-tion of adoption of a built environment, change in dietconsistency, and lowered mobility brought about mor-phological changes similar to those seen in certain do-mestic animals. If future collaborative studies by bio-logical anthropologists and archaeozoologists confirm

these trends in other regions and reach agreement thatthey constitute evidence for the domestication of hu-mans, just how many of the other classic criteria of do-mestication might be detected? It could prove even morechallenging to determine whether humans display thechanges in fat storage, sexuality, frequency of multiplebirths, declining sensory acuity, and docility claimed forother domestic animals.

Comments

colin grovesSchool of Archaeology and Anthropology, AustralianNational University, Canberra, A.C.T. 0200, Australia([email protected]). 8 i 03

In this useful and thought-provoking paper, Leach setsout the characteristics to be expected in domestic ani-mals and their differences from wild ones, and she drawsthe striking parallels with late human evolution thathave been ignored by all but a handful of anthropologistsover the past half-century. I am going to propose modi-fications to part of her model, but I fully accept the com-parative method on which it is based.

Cartmill (1990) has pointed out that, if the anthro-pological sciences are ever to become truly scientific,their practitioners must stop assuming human unique-ness; unique events are immune to theoretical expla-nations, and only the comparative method can throw uptestable hypotheses. The changes that occurred in theterminal stages of human evolution parallel those thatoccurred in mammals under domestication. Moreover,the relationship between humans and domestic animalsis a form of symbiosis or mutualism (see, in addition toLeach, Zeuner 1963 and O’Connor 1997). An importantpart of the environment of a species is other species—notmerely its predators and pathogens but its symbionts.

Leach criticizes Allman’s proposal that the parallelismin brain size reduction in dogs and in humans can beattributed to agriculture “and other cultural means,” ar-guing that in humans the decrease in brain size was sim-ply an aspect of decrease in body size. I will show thatthis is not so.

The amount by which the brain was reduced in dif-ferent domestic species is very controversial; the figurescited by Herre and Rohrs (1977) are much higher thanthose given by Hemmer (1976, 1990). We do know thatthere has been a decrease and that it tends to be differ-ential—from least to most reduced, midbrain and me-dulla r cerebellum r forebrain in general and corpuscallosum r limbic system (Herre and Rohrs 1977). Allthis adds up to what Hemmer (1983) called Verarmungder Merkwelt (“the decline of environmental apprecia-tion”), and he sees changes such as the heterochronicchanges in the facial skeleton as closely linked to it.

I cannot concur with Leach’s distinction between ge-netic and ecophenotypic effects. Ecophenotypic effects




are unlikely to persist over many generations; they aredestined almost inevitably to become part of the genomeby what is known as the Baldwin effect (Baldwin 1896:144; see also Dennett 1995): “Of all the variations tend-ing in the direction of an adaptation, but inadequate toits complete performance, only those will be supple-mented and kept alive which the intelligence ratifiesand uses.”

Leach agrees with Allman on parallel changes betweenhumans and domestic animals and on the reason forthem: “Village life,” she writes here, “similarly offeredprotection to human populations,” and she ascribes post-Pleistocene decreases in size in humans to this effect.Later she suggests that a climatic effect on size and ro-busticity is feasible but “the built environment of thesedentary group modifies the microclimate experiencedby its occupants.” But body size reduction occurred notonly in sedentary populations but also in hunter-gath-erers such as Aboriginal Australians (Brown 1987) andin indigenous South Africans (Brauer 1989:16). Beforeasking why, we must ask when. “At the close of thePleistocene,” says Leach, but in the preceding paragraphshe has cited evidence that in Europe it started after theLast Glacial Maximum. If this is so, then even in Europeit could not have been due to sedentism and village life.

And shall we link size and cranial capacity? Accordingto Lahr (1996:246), “cranial height commonly increasedas gracilization occurred,” but cranial height and gracil-ity are not themselves complete proxies for brain sizeand body size. The changes in stature and cranial ca-pacity in Europe from the Upper Palaeolithic to the pres-ent do not in fact track each other. Stature declines fromthe Upper Palaeolithic to the Eneolithic and then in-creases again, whereas cranial capacity increases slightlyuntil the Mesolithic but thereafter exhibits an unbrokendecline (Groves 1999). Stature declines are less quanti-fiable outside Europe, but decreases in cranial capacityare as marked and certainly apply to Africa.

There has, then, been genuine brain size reductionin humans, and it is not merely an aspect of body sizereduction. What I have proposed (Groves 1999) is thathumans have undergone a reduction in environmentalawareness in parallel to domestic species and for ex-actly the same reason. Domestication is a symbiosis;each partner is, to a degree, sheltered by its associationwith the other. In most cases the nonhuman partner issheltered far more than the human, but in one case thepartnership is more mutual. The social organizationsof human and dog are well integrated, suggesting thatthe symbiosis is of long standing. Vila et al. (1997) foundthat dog mitochondrial lineages are as distinct fromthose of wolves as are those of the geographic groupingsof wolves from each other; I have argued that the ageof this separation could be as much as 143,000 to229,000 years b.p. “Dogs acted as humans’ alarm sys-tems, trackers and hunting aides, garbage disposal fa-cilities, hot water bottles, and children’s guardians andplaymates. Humans provided dogs with food and se-curity. The relationship was stable over 100,000 yearsor so, and intensified in the Holocene into mutual do-

mestication. Humans domesticated dogs, and dogs do-mesticated humans” (Groves 1999:11).

terry o’connorDepartment of Archaeology, University of York, YorkYO1 7EP, U.K. ([email protected]). 6 i 03

It is always satisfying to read a paper that takes a co-herent body of evidence and pursues it to its logical con-clusion, which is essentially what Leach has achievedin her concise review of a contentious topic. If the cri-teria by which “domestication” is recognized in othermammals are applied to Late Pleistocene and HoloceneHomo sapiens, it is difficult to escape the conclusionthat something similar has occurred in our species. It isdifficult, too, to escape the conclusion that terminologyand semantics inform this debate more strongly thandoes the hard evidence. As Leach says of Holocene sizechange, “while the trends in animals are widely acceptedas evidence of domestication, in humans this is notviewed as an option.” Indeed, because by consensus def-inition “domestication,” whether as event or process, isnot referable to humans. This is not to gainsay the casethat Leach makes. Rather, I would argue that it showsthe poor utility of our current terminology, derived as itis from an inadequate, narrow perspective. We need anew paradigm which encompasses all aspects of the co-evolution of the plants and animals of the human domus,including us. Such a paradigm would include the behav-ioural and somatic consequences of that coevolution inall species.

What of those consequences? Perhaps we run the riskof too readily discarding deliberate selection. Leach sug-gests that the anatomical response to a shared diet mayexplain the craniofacial and dental changes seen in co-habiting dogs, pigs, and people. Maybe so, and the ana-tomical evidence is compelling. However, we might keepa place for human selection in favour of the shorter,wider face that makes dogs and pigs look more “human,”more like one of the family, when surplus puppies wereculled or piglets chosen for the pot. That is a minor point:the big issue that this paper throws open is the extentto which Holocene lifeways have influenced recent hu-man evolution. Leach draws attention to Trutt’s workon silver foxes and the anatomical consequences of se-lecting against aggressive behaviour. If, as Trutt pro-posed, the adrenal cortex and serotonin system were im-plicated in these changes, we might wonder whetherfalling sperm counts and escalating depressive illness inmodern European males could both be a side-effect ofsimilar unconscious selection. Leach’s discussion of hu-man domestication is of more than academic interest ifit leads us to consider such possibilities, and that is oneof its merits.

Turning to Leach’s review of past debate in this area,it is good to see Franz Boas’s work on the subject givendue credit and sad to reflect on the damage that mid-20th-century racism managed to do to any intelligentdiscussion of human variation. Perhaps another barrier




to wider recognition of Boas’s work is that the termi-nology of his day was inadequate to express clearly thedirection that his thoughts seem to have been taking—anissue that some of us would argue bedevils the subjecttoday. Discussion of domestication inevitably goes backto Darwin’s 1868 volume, and Leach credits Darwin withrecognizing the effects of unconscious selection. Cer-tainly Darwin seems to be referring to something thatwe might recognize as unconscious selection when heobserves that “he [i.e., that 19th-century paragon, Man]unintentionally exposes his animals and plants to vari-ous conditions of life, and variability supervenes, whichhe cannot even prevent or check” (1868, vol. 1:2). How-ever, a couple of pages farther on, domestication seemsto be a more deliberate process “as the will of man thuscomes into play” (1868, vol. 1:4). Something of that un-certainty underlies our modern discussions. If domesti-cation is necessarily a deliberate process, then it is notappropriate to speak of human domestication becausehumans do not selectively breed for particular traits. (Atleast, one hopes not.) However, if domestication of otherspecies has a component of unconscious selection, thensurely we must consider the possibility that we too havebeen subject to that process. Notwithstanding Darwin’snifty footwork with regard to selection processes, he,Wallace, Huxley, and their contemporaries stressed thefundamental fact that no species is immutable. And thatincludes us. What Leach has done is to open up the dis-cussion of our mutability in an important and challeng-ing direction.

osbjorn pearsonDepartment of Anthropology, University of NewMexico, Albuquerque, N.M. 87131, U.S.A. ([email protected]). 10 i 03

Leach presents the interesting hypothesis that humanshave undergone a domestication process producing mor-phological and behavioral changes that parallel thosethat distinguish domestic animals from their wild an-cestors. Specifically, she proposes that the decreases inbody, brain, facial, and dental size that affected agricul-tural populations stem from the same processes apparentin domestic animals. Space restrictions limit my com-ments to some specific points that contradict her mainhypothesis, but there is still much to commend inLeach’s article.

The process of facial and dental reduction began longbefore agriculture (Weidenreich 1937, 1943), but thespread of agriculture and the development of more effi-cient cooking and food processing accelerated it (Brace,Rosenberg, and Hunt 1987, Calcagno 1989). The firstmodern humans at 130,000 years b.p. had much smallerfaces than archaic hominines (Day and Stringer 1991,Lieberman, McBratney, and Krovitz 2001).

Substantial facial and dental reduction did follow theadoption of agriculture (Calcagno 1989), but in a fewinstances hunter-gatherers also experienced substantialcranial reduction. Brown (1989, 1993) has noted that late

Holocene southeastern Australians males experienced a9% decline in facial volume and cranial capacity and a3% decline in dental dimensions relative to terminalPleistocene males from Coobool Creek and other sites.Populations in southeastern Australia were fairly sed-entary (Pardoe 1995, Mulvaney and Kamminga 1999)—which could support the domestication hypothesis—butlate Holocene crania from other parts of Australia arealso smaller than the Coobool Creek crania (Brown1989). Cranial gracilization in the Holocene may havebeen universal in Australia. African hunter-gatherersprovide two additional examples of cranial gracilization.San and especially “pygmy” crania and body size arequite small by worldwide standards and much smallerthan those of the earliest modern humans (Keith 1925,Eveleth and Tanner 1990). These declines in size conflictwith the domestication hypothesis.

Human sexual dimorphism also reached its currentlevel long before the origin of agriculture. Lower sexualdimorphism in mammals is generally linked with lessmale-male competition for mates (Plavcan 2002). EarlyKenyan H. erectus is the first hominine to have had adegree of dimorphism similar to that of modern humans(Walker 1993, Kappelman 1996). H. erectus fossils fromSwartkrans display a greater degree of sexual dimor-phism (Susman, de Ruiter, and Brain 2001), but by300,000 years b.p. H. heidelbergensis from Atapuercaclearly displays a modern degree of dimorphism in bodysize (Arsuaga et al. 1997, Lorenzo et al. 1998). It is rea-sonable to assume that these hominines had social sys-tems and degrees of male-male competition similar tothat of modern humans. Modern humans are remarkablefor the amount of cooperation, sharing, and reciprocalaltruism that typifies our societies, especially those ofhunter-gatherers (Gurven, Hill, and Kaplan 2002). Co-operation was likely vital for survival in a foraging econ-omy. This degree of mutualism is probably possible onlyif intrasexual competition is kept in check. A similartrend toward cooperation and sharing with conspecificsdoes not characterize domestic animals.

Declines in human stature do not unequivocally sup-port Leach’s hypothesis. Improvements in health and nu-trition over the past 200 years have led to a marked in-crease in stature, and Europeans are now as tall as theirPaleolithic ancestors (Walker 1993). Environmental in-fluences rather than genetic change appear to be respon-sible for these changes. The Neolithic decline in bodysize differs from the intentional selection for smaller,more manageable beasts during animal domestication.

Finally, as Leach notes, research on the putative re-duction in limb robusticity following the spread of ag-riculture has been plagued by the use of the same word,“robusticity,” to describe different physical traits (Pear-son 2000). In terms of residual strength (bone strengthrelative to body size), no single trend of increase or de-crease can be considered to have been in operation sincethe origin of modern humans. The data I have examined(Pearson 2000) show that levels of diaphyseal versus ep-iphyseal robusticity for the femur and humerus presentfew clear, overarching trends with the adoption of agri-




culture or sedentary lifestyles. Some hunter-gathererssuch as Australian Aborigines had very high levels ofresidual humeral strength, exceeding even those ofNeandertals, while others such as Gravettian Europeanshad lower levels of residual humeral strength than manyrecent sedentary agricultural or industrial populations.In the lower limb there appears to be a clearer patternin which the less sedentary groups appear to have greaterresidual strength in the femur and tibia.

melinda a. zederArchaeobiology Program, Department ofAnthropology, National Museum of Natural History,Smithsonian Institution, Washington, D.C. 20013-7012, U.S.A. ([email protected]). 30 i 03

The central premise of this provocative essay is that thesame unconscious selective pressures involved in animaldomestication also operated on humans adopting sed-entary lifestyles and that in both cases these pressuresare linked to decreased mobility, changes in diet consis-tency, and the effects of the “built environment.” Leachfails to make a convincing case for this thesis in threecritical areas.

The most basic fault lies in the unconvincing parallelsdrawn between the morphological impacts of domesti-cation on animals and sedentism on humans. Whileoverlapping factors (environment, diet, selection forgreater passivity) may contribute to size change in bothanimals undergoing domestication and humans adoptingsedentism, other processes that affect size in these spe-cies (e.g., general post-Pleistocene size reduction inmammals) operate independently of both domesticationand sedentism. Moreover, data on the degree and timingof size change in both domesticates and humans are fartoo sketchy to support the conclusion that the changesin question stem from the same overarching process. Re-duction in cranial robusticity in domesticates is clearlynot evident in humans. Arguments for reduction in cra-nial capacity in domestic animals are subject to the sameallometric scaling concerns that undermine assertionsthat humans who adopted sedentary lifestyles experi-enced brain size reduction. The cranio-facial and dentalchanges in domesticates such as pigs and dogs have beenconvincingly linked to paedomorphic factors related tojuvenilization of behavior and early onset of sexual ma-turity. Leach arbitrarily attributes these changes to thesame dietary shifts held responsible for similar changesin humans, but there is simply no evidence for the adop-tion of “soft diets” in the majority of domestic animals.

The second fault is the conflation of the proximatecausal factors for noted morphological changes in ani-mals and humans with the contexts in which they op-erate. Both domestication and sedentism may select forsmaller individuals better able to survive on impover-ished diets, for early onset of sexual maturity and a shiftfrom K- to r- reproductive rates, and even for less ag-gressive behaviors. These similar selection pressuresmay in turn be manifested in similar morphological

changes in humans and animals. But this does not meanthat domestication and sedentism are one and the same.

And herein lies the essay’s most serious failing. ForLeach, denying human intentionality in animal domes-tication seems to clear the way for the conflation of do-mestication and sedentism under the rubric of uncon-scious selective factors experienced by both humans andanimals residing in the “built environment.” There canbe no question that domestication is a coevolutionaryprocess in which humans and a target animal (or plant)species enter into a mutualistic and largely symbioticrelationship that enhances the selective fitness of both.It is also true that many of the evolutionary impacts onanimal and plant partners are part of a general “adaptivesyndrome of domestication” that happens without de-liberate, conscious human direction. But this does notmean that human intentionality is entirely absent.While humans may not intentionally select for any ofthe adaptive features that make certain target speciesattractive domesticates, they do opt to nurture, protect,and selectively propagate these species at the expense ofother potential resources. And they do so with the goalof a more predictable and secure subsistence base. In-deed, it is this element of human deliberation and con-scious directed behavior that distinguishes domestica-tion from other mutualistic relationships such ascommensalisms. Neither the intricate symbiotic mu-tualism between ants and fungus nor the semiparasiticrelationship between sparrows/mice and humans cancompare to deliberate human propagation of domesticpartner species, human transport and nurturing of thesespecies outside their original habitats, and human mod-ification of landscapes and restructuring of ecosystemsas part of the intensification of agricultural economies.

Sedentism results from quite another set of humandecisions directed at framing a subsistence base capableof supporting a community in a single location for muchof the seasonal cycle. In many cases this base includesdomesticated species, but in certain resource-rich envi-ronments people have been able to construct subsistencebases that support large and fully sedentary communitieswithout them. Moreover, in Mesoamerica squash, corn,and beans, domesticated serially over the course of sev-eral millennia, played minor roles in the shifting roundof mobile foragers for at least 5,000 years before seden-tary communities based on agricultural production wereestablished.

Goals of promoting security and predictability andmaximizing yields may help guide both domesticationand sedentism, but the interspecific coevolutionary re-lationships fundamental to domestication are absent insedentism. Nor do the social forces that help draw andbind humans together in sedentary communities figuredirectly in domestication. To conflate domestication andsedentism does nothing to illuminate the causes, thecourse, or the consequences of arguably the two mostsignificant transformative processes in human history.




Reply

helen m. leachDunedin, New Zealand. 3 ii 03

I am grateful to the commentators who responded to thispaper. It is a product not of personal fieldwork or labo-ratory research in archaeozoology or palaeoanthropologybut of the “chalk-face” where teachers attempt to in-tegrate evidence and explanations produced by manysub-disciplines of anthropology into a coherent accountof human prehistory. For three decades I have team-taught undergraduate courses on human evolution andprehistory, including the origins of food production. Fol-lowing the lead of widely used introductory textbooks,we have taught the Palaeolithic stages largely as a nar-rative of biological evolution, with brief excursions intostone technology and subsistence. In contrast, we pre-sent Holocene prehistory as the story of cultural evo-lution, and the standard texts (which happily discusssuch details as the retromolar gap in Neanderthals) gen-erally ignore the physical anthropology of Halafians, Su-merians, Egyptians, and others as they move on to theorigins of civilization. The physical changes occurringin post-Pleistocene Homo sapiens are relegated to text-books on physical anthropology, where they are consid-ered as examples of human variation.

While the mainstream texts set human biological evo-lution aside at about the time that Magdalenians weretaking up their paintbrushes, they see no discrepancy indiscussing the skeletal morphology of domesticatedgoats or pigs at the onset of the Holocene. One possibleexplanation lies in the widely accepted definition of adomestic animal, which makes it like an artefact, thesubject of ownership, and allows domestic animals to bediscussed alongside other subsistence-related artefacts.Another explanation relates to the pervasive notion inwritings about prehistory that as culture increasinglybuffered humans from the cold winds of natural selec-tion, human biological evolution became unimportant.Such paradigms have led us to the present situation inwhich archaeozoologists working exclusively on animalsand physical anthropologists working on humans addressdifferent questions framed within different temporalscales.

While the archaeozoologists studying animal domes-tication observe morphological changes over a few thou-sand years, the palaeoanthropologists often comparetheir recent samples with Pleistocene specimens tens ofthousands of years older and potentially members of dif-ferent species. These differing perspectives have madethe comparisons attempted in this paper difficult and liebehind some of the criticisms raised by the commen-tators (e.g., Pearson’s). For example, when viewed overthe past 300,000 years, variation in cranial robusticityin Homo is often linked to speciation, while changesobserved over the last 40,000 years have been attributedto cultural evolution in technology (e.g., Frayer 1980).

When they are observed across the Pleistocene-Holocenetransition in Australia, they are seen as a possible re-sponse to Holocene warming (Brown 1987:62), but co-inciding with the transition to agriculture they are pre-sented as a response to a softer diet (Larsen 1995:196).Distinguishing short-term local variation from long-term evolutionary trends is a challenge that needs to beaddressed at an interdisciplinary level.

Besides problems of scale, this research encounteredlong-standing disagreements in the definition and usageof terms such as “domestication,” “robusticity,” and“unconscious selection.” While palaeoanthropologistshave made progress with the recognition of a complexof features that make up “robusticity” (e.g., Lahr 1996,Pearson 2000), “unconscious selection” remains un-wieldy. I have provided examples of its use, but the termclearly encompasses too much. The argument can bemade that humans have so greatly altered the planet andits climate that virtually no selection process is truly“natural” any more. If we retain the concept of “artificialselection” for voluntary and informed selective breedingof animals and plants by humans, then the middleground of unconscious or involuntary selection becomesunmanageably wide and requires subdivision. Bell’s(1997:80–84) “unintentional” selection (as in pesticideresistance) and “accidental” selection (as in industrialmelanism) might be useful additional terms.

O’Connor calls for a new paradigm and terminologyfor the coevolution that occurred in the domus. I wouldhappily adopt one provided that it could accommodateand distinguish the range of factors now known to affectthe coevolving species. For a start, the so-called criteriaof animal domestication need to be disassembled and theontogenetic mechanisms producing them more fully in-vestigated. In the past these criteria have been treatedas isolated traits, usually resulting from deliberate se-lection, but increasingly the changes are being assignedto other selection pressures. Some would save “domes-tication” just for the process and consequences of selec-tive breeding, but as long as it covers the results of un-conscious selection as well humans cannot logically beexcluded.

Pearson’s reading of my paper emphasizes agricultureas the prime factor in producing the morphologicalchanges in humans and domestic animals, and in rebut-tal he lists cases of facial and dental reduction in hunter-gatherers who were neither sedentary nor adopting ag-riculture. However, I tried to keep changes in foodtechnology and the built environment separate from thetransition to agriculture, since we have evidence of food-grinding equipment and semi-permanent house con-struction several millennia before signs of animal orplant domestication. Certainly agriculture accentuatedthe changes in diet consistency and the built environ-ment, but in many parts of the world it did not initiatethem.

On reflection, the built environment is not the onlymeans whereby humans can modify their personal cli-mate. Well-designed clothing permitted the Inuit towork outside with bodies only moderately adapted to the




cold. They were less robust than the Fueguians, whoseadaptation to extreme wind-chill conditions seems tohave been largely biological and not reliant on clothingor housing (Lahr 1996:263; Hernandez, Lalueza Fox, andGarcia-Moro 1997:105). A hypothesis that human cranialrobusticity is linked to biological adaptation to the coldand is reduced with cultural innovations in clothing andhousing is not inconsistent with Brown’s (1987) argu-ment that it was Holocene warming that led to reductionin cranial robusticity in Australian Aboriginals, sincethey did not employ elaborate cultural means of personalclimate control. In the case of the Polynesians, Houghton(1996) maintains that a biological adaptation to the coldconditions of open ocean voyaging (where it is extremelydifficult to keep the body dry or warm) kept Polynesiansmore robust than might be expected from their tropicalisland environment (see also Visser and Dias 1999).

Groves supports Allman’s contention that brain sizehas decreased not only absolutely but relatively and at-tributes this to Hemmer’s “decline in environmental ap-preciation.” But, as I stated, Allman’s source referredonly to an absolute decrease in cranial capacity, and thisis also the view of Henneberg (1997:fig. 4, 6) and severalauthors quoted by him. If a relative decrease is also thecase, I find Hemmer’s mechanism less convincing thanthe arguments that try to come to terms with mechan-ical loadings and cranial ontogeny. Though some captivehumans have endured confinement comparable to thatof domestic animals, we have no evidence that early vil-lage life was less stimulating than that of a mobilehunter-gatherer. What was lost in encounters with nat-ural phenomena may have been compensated for by in-creased social stimulation as group sizes increased. (Iwould accept, however, that males’ control over theirdaughters’ breeding partners may have been strength-ened with the construction of solid-walled housingcomplexes.)

I share Zeder’s commitment to understanding two ofthe most significant transformative processes affectinghuman history: sedentism and domestication. But whileshe finds the parallels I drew between the morphologicalimpacts of domestication on animals and sedentism onhumans unconvincing, this is precisely how many stu-dents view the differing explanations which archaeo-zoologists have offered for similar changes occurring inequids, suids, other ungulates, and canids. Given themorphological changes also apparent in humans, the stu-dent is justified in asking why similar phenomena re-quire so many different causes. The core of my paper wasa demonstration of this unsatisfactory diversity of ex-planations and the development of the proposition thatwe should not expect humans to be unaffected physicallyby the environment, lifestyle, and diets which theyshared to varying degrees with their domesticates.

The links I drew with sedentism were an attempt tobreak the long-standing causal relationships posited be-tween the morphological changes in humans and thetransition to agriculture. Having been charged with con-flating domestication and sedentism (Zeder) and domes-tication and agriculture (Pearson), I more fully appreciate

the problems created by using these labels. Without em-ploying them, my argument (restated) was that substan-tial housing and, I would now add, thermo-insulativeclothing, decreased mobility, and reduction in the fibrecontent and particle size of food all modified the selec-tion pressures on humans. Neither sedentism nor theadoption of agriculture is a prerequisite, though both cre-ated favourable conditions for these modifications to oc-cur. Similar selection pressures affected animals thatcoevolved with humans wherever they were providedwith shelter and protection from predators, had theirwild-type diet altered, and/or were subject to differentmechanical loadings on their bodies. In addition, thetransmission of animal genes was affected by consciousbreeding decisions by humans. But rather than seeingthe changes in domestic animals as phenomena specificto them, a position which overemphasizes the role ofselective breeding, I called for greater integration of theevidence of morphological change in both humans andanimals.

The explosion of data and the complexity of currentanalytical methods have understandably encouraged thedevelopment of sub-divisions within anthropology. Fromtime to time it is a worthwhile exercise for teachers ofthe subject and writers of textbooks to attempt to cor-relate the findings of these specialist fields and commenton the discrepancies.

References Cited

a l l m a n , j o h n m . 1999. Evolving brains. New York: Scien-tific American Library.

a n g e l , j . l a w r e n c e . 1984. “Health as a crucial factor inthe changes from hunting to developed farming in the EasternMediterranean,” in Paleopathology at the origins of agricul-ture. Edited by M. N. Cohen and G. Armelagos, pp. 51–73. Or-lando: Academic Press.

a r s u a g a , j . l . , j . m . c a r r e t e ro , c . l o r e n z o , a .g a r c i a , i . m a r t ı n e z , j . m . b e r m u d e z d e c a s -t ro , a n d e . c a r b o n e l l . 1997. Size variation in MiddlePleistocene humans. Science 277:1086–88. [op]

b a g e h o t , w a l t e r . 1905. Physics and politics, or Thoughtson the application of the principles of “natural selection” and“inheritance” to political society. London: Kegan Paul, Trench,Trubner.

b a l d w i n , j . m a r k . 1896. A new factor in evolution. Ameri-can Naturalist 30:441–51. [cg]

b a r - y o s e f , o f e r , a n d r i c h a r d h . m e a d o w. 1995.“The origins of agriculture in the Near East,” in Last hunters,first farmers: New perspectives on the prehistoric transition toagriculture. Edited by T. D. Price and A. B. Gebauer, pp. 39–94.Santa Fe: School of American Research Press.

b e l l , g r a h a m . 1997. Selection: The mechanism of evolution.New York: Chapman and Hall.

b e n d e r , b a r b a r a . 1975. Farming in prehistory: Fromhunter-gatherer to food-producer. London: John Baker.

b e r ry, r . j . 1969. “The genetical implications of domestica-tion in animals,” in The domestication and exploitation ofplants and animals. Edited by P. J. Ucko and G. W. Dimbleby,pp. 207–17. London: Duckworth.

b i t t e l , j . 1992. The different types of general cold adaptationin man. International Journal of Sports Medicine 13:S172–76.




b o a s , f r a n z . 1938. The mind of primitive man. New York:Macmillan.

b o g i n , b . , a n d r . k e e p . 1999. Eight thousand years of eco-nomic and political history in Latin America revealed by an-thropometry. Annals of Human Biology 26:333–51.

b o k o n y i , s a n d o r . 1989. “Definitions of animal domestica-tion,” in The walking larder: Patterns of domestication, pas-toralism, and predation. Edited by J. Clutton-Brock, pp. 22–27.London: Unwin Hyman.

b o u r s o t , p . , j . - c . a u f f r a y, j . b r i t t o n - d a v i d i a n ,a n d f . b o n h o m m e . 1993. The evolution of house mice.Annual Review of Ecology and Systematics 24:119–52.

b r a c e , c . l o r i n g . 1978. Tooth reduction in the Orient.Asian Perspectives 19:203–19.

b r a c e , c . l o r i n g , k a r e n r . ro s e n b e r g , a n d k e v i nd . h u n t . 1987. Gradual change in human tooth size in thelate Pleistocene and post-Pleistocene. Evolution 41:191–204.[op]

b r a u e r , g . 1989. “Prehistoric and historic populations,” inRassengeschichte der Menschheit, Afrika 2, Sudafrika. Editedby Ilse Schwidetzy, pp. 12–71. Munich: R. Oldenbourg Verlag.[cg]

b r i d g e s , p a t r i c i a . 1989. Changes in activities with theshift to agriculture in the Southeastern United States. currentanthropology 30:385–94.

b ro w n , p e t e r . 1987. Pleistocene homogeneity and Holocenesize reduction: The Australian human skeletal evidence. Ar-chaeology in Oceania 22:41–71. [cg]

———. 1989. Coobool Creek: A morphological and metricalanalysis of the crania, mandibles, and dentitions of a prehis-toric Australian human population. Vol. 13. Terra Australis.Canberra: Department of Prehistory, Research School of PacificStudies, The Australian National University, Canberra. [op]

———. 1993. “Recent human evolution in East Asia and Austra-lia,” in The origin of modern humans and the impact ofchronometric dating. Edited by M. J. Aitken, C. B. Stringer,and P. A. Mellars, pp. 217–33. Princeton: Princeton UniversityPress. [op]

b u i k s t r a , j a n e e . 1984. “The Lower Illinois River region: Aprehistoric context for the study of ancient diet and health,” inPaleopathology at the origins of agriculture. Edited by M. N.Cohen and G. Armelagos, pp. 215–34. Orlando: AcademicPress.

c a l c a g n o , j a m e s m . 1989. Mechanisms of human dentalreduction: A case study from Post-Pleistocene Nubia.Lawrence: Department of Anthropology, University of Kansas.[op]

c a r l s o n , d a v i d . 1976. “Patterns of morphological variationin the human midface and upper face,” in Factors affecting thegrowth of the midface. Edited by J. A. McNamara Jr, pp.277–99. Ann Arbor: University of Michigan Press.

c a r t m i l l , m a t t . 1990. Human uniqueness and theoreticalcontent in paleoanthropology. International Journal of Prima-tology 11:173–92. [cg]

c h i l d e , v e r e g o r d o n . 1928. The most ancient East: TheOriental prelude to European prehistory. London: Kegan Paul,Trench, Trubner.

c h u r c h i l l , s t e v e n e . 1998. Cold adaptation, heterochrony,and Neandertals. Evolutionary Anthropology 7:46–60.

c i o c h o n , ro b e r t l . , r . a . n i s b e t t , a n d r . s . c o r -ru c c i n i . 1997. Dietary consistency and craniofacial develop-ment related to masticatory function in minipigs. Journal ofCraniofacial Genetics and Developmental Biology 17:96–102.

c l u t t o n - b ro c k , j u l i e t . 1963. “The origins of the dog,” inScience in archaeology. Edited by D. Brothwell and E. Higgs,pp. 269–74. London: Thames and Hudson.

———. 1969. “Carnivore remains from the excavations of theJericho Tell,” in The domestication and exploitation of plantsand animals. Edited by P. J. Ucko and G. W. Dimbleby, pp.337–45. London: Duckworth.

———. 1992. How the wild beasts were tamed. New Scientist133(1808):41–43.

———. 1999. 2d edition. A natural history of domesticatedmammals. Cambridge: Cambridge University Press.

c o h e n , m a r k n a t h a n . 1989. Health and the rise of civili-zation. New Haven: Yale University Press.

c o h e n , m a r k n a t h a n , a n d g e o r g e a r m e l a g o s .Editors. 1984. Paleopathology at the origins of agriculture. Or-lando: Academic Press.

c o l l i e r , s t e p h e n . 1993. Sexual dimorphism in relation tobig-game hunting and economy in modern human populations.American Journal of Physical Anthropology 91:485–504.

c o o k , d e l l a c o l l i n s . 1984. “Subsistence and health inthe Lower Illinois Valley: Osteological evidence,” in Paleo-pathology at the origins of agriculture. Edited by M. N. Cohenand G. Armelagos, pp. 235–69. Orlando: Academic Press.

d a r w i n , c h a r l e s . 1868. The variation of animals andplants under domestication. 2 vols. London: John Murray.

d a v i s , s i m o n j . m . 1981. The effects of temperature changeand domestication on the body size of Late Pleistocene to Ho-locene mammals of Israel. Paleobiology 7:101–14.

d a v i s , s i m o n j . m . , a n d f . v a l l a . 1978. Evidence fordomestication of the dog 12,000 years ago in the Natufian ofIsrael. Nature 276:608–10.

d a y, m i c h a e l h . , a n d c h r i s t o p h e r b . s t r i n g e r .1991. Les restes craniens d’Omo-Kibish et leur classification al’interieur du genre Homo. L’Anthropologie 95:573–94. [op]

d e n n e t t , d a n i e l c . 1995. Darwin’s dangerous idea: Evolu-tion and the meanings of life. New York: Simon and Schuster.[cg]

d i c k e l , d a v i d n . , p e t e r d . s c h u l z , a n d h e n ry m .m c h e n ry. 1984. “Central California: Prehistoric subsis-tence changes and health,” in Paleopathology at the origins ofagriculture. Edited by M. N. Cohen and G. Armelagos, pp.439–61. Orlando: Academic Press.

d o b z h a n s k y, t h e o d o s i u s . 1962. Mankind evolving. NewHaven: Yale University Press.

e d y n a k , g l o r i a y ’ . 1978. Culture, diet, and dental reduc-tion in Mesolithic forager-fishers of Yugoslavia. current an-thropology 19:616–18.

———. 1989. Yugoslav Mesolithic dental reduction. AmericanJournal of Physical Anthropology 78:17–36.

e i b l - e i b e s f e l d t , i r e n a u s . 1970. Ethology: The biology ofbehavior. New York: Holt, Rinehart and Winston.

e r i c s o n , p e r g . p . , t o m m y t y r b e r g , a n n a s t i n ak j e l l b e r g , l e i f j o n s s o n , a n d i n g a u l l e n . 1997.The earliest record of house sparrows (Passer domesticus) innorthern Europe. Journal of Archaeological Science 24:183–90.

e v e l e t h , p h y l l i s b . , a n d j a m e s m . t a n n e r . 1990. 2dedition. Worldwide variation in human growth. Cambridge:Cambridge University Press.

f l o u d , ro d e r i c k , k e n n e t h w a c h t e r , a n d a n n a -b e l g r e g o ry. 1990. Height, health and history: Nutritionalstatus in the United Kingdom, 1750–1980. Cambridge: Cam-bridge University Press.

f o r m i c o l a , v i n c e n z o , a n d m o n i c a g i a n n e c -c h i n i . 1999. Evolutionary trends of stature in Upper Paleo-lithic and Mesolithic Europe. Journal of Human Evolution 36:319–33.

f r a y e r , d a v i d w. 1980. Sexual dimorphism and culturalevolution in the Late Pleistocene and Holocene of Europe.Journal of Human Evolution 9:399–415.

g o o d m a n , a l a n , d e b r a l . m a r t i n , g e o r g e j . a r -m e l a g o s , a n d g e o r g e c l a r k . 1984. “Indications ofstress from bone and teeth,” in Paleopathology at the originsof agriculture. Edited by M. N. Cohen and G. Armelagos, pp.13–49. Orlando: Academic Press.

g r i g s o n , c a ro l i n e . 1969. “The uses and limitations of dif-ferences in absolute size in the distinction between the bonesof aurochs (Bos primigenius) and domestic cattle (Bos taurus),”in The domestication and exploitation of plants and animals.Edited by P. J. Ucko and G. W. Dimbleby, pp. 277–94. London:Duckworth.

g ro v e s , c o l i n p . 1999. The advantages and disadvantages of




being domesticated. Perspectives in Human Biology 4:1–12.[cg]

g u rv e n , m i c h a e l , k i m h i l l , a n d h i l l a r d k a p l a n .2002. From forest to reservation: Transitions in food-sharingbehavior among the Ache of Paraguay. Journal of Anthropologi-cal Research 58:93–120. [op]

h a l l , s t e p h e n j . g . 1993. “Why are there so many breedsof livestock?” in Skeletons in her cupboard: Festschrift for Ju-liet Clutton-Brock. Edited by A. Clason, S. Payne, and H.-P.Uerpmann, pp. 99–107. Oxbow Monograph 34.

h e m m e r , h e l m u t . 1976. Man’s strategy in domestication: Asynthesis of new research trends. Experientia 32:663–66. [cg]

———. 1983. Domestikation: Verarmung der Merkwelt. Braun-schweig: Vieweg. [cg]

———. 1990. Domestication: The decline of environmental ap-preciation. Cambridge: Cambridge University Press.

h e n n e b e r g , m a c i e j . 1997. Human evolution today: Whichway next? Perspectives in Human Biology 3:1–12.

h e r n a n d e z , m i q u e l , c a r l e s l a l u e z a f o x , a n dc l a r a g a r c i a - m o ro . 1997. Fueguian cranial morphology:The adaptation to a cold, harsh environment. American Jour-nal of Physical Anthropology 103:103–17.

h e r r e , w o l f , a n d m a n f r e d ro h r s . 1977. “Zoologicalconsiderations on the origins of farming and domestication,”in Origins of agriculture. Edited by C. A. Reed, pp. 245–79.The Hague: Mouton.

h o d d e r , i a n . 1990. The domestication of Europe: Structureand contingency in Neolithic societies. Oxford: BasilBlackwell.

h o l e , f r a n k , k e n t v. f l a n n e ry, a n d j a m e s a .n e e l y. 1969. Prehistory and human ecology of the DehLuran Plain. Memoirs of the Museum of Anthropology, Uni-versity of Michigan 1.

h o l l i d a y, t r e n t o n w. 1999. Brachial and crural indices ofEuropean Late Upper Paleolithic and Mesolithic humans. Jour-nal of Human Evolution 36:549–65.

h o l l i d a y, t r e n t o n w. , a n d a . b . f a l s e t t i . 1995.Lower limb length of European early modern humans in rela-tion to mobility and climate. Journal of Human Evolution 29:141–53.

h o u g h t o n , p h i l i p . 1996. People of the great ocean. Cam-bridge: Cambridge University Press.

j a c k e s , m a ry, d a v i d l u b e l l , a n d c h r i s t o p h e rm e i k l e j o h n . 1997. Healthy but mortal: Human biology andthe first farmers of Western Europe. Antiquity 71(273):639–58.

j a c k s o n , s u e , a n d j a r e d d i a m o n d . 1996. Metabolicand digestive responses to artificial selection in chickens. Evo-lution 50:1638–50.

j a c o b s , k e n n e t h h . 1993. Human postcranial variation inthe Ukrainian Mesolithic-Neolithic. current anthropology34:311–24.

j a r m a n , m i c h a e l r . , a n d p a u l w i l k i n s o n . 1972.“Criteria of animal domestication,” in Papers in economic pre-history: Studies by members and associates of the BritishAcademy major research project in the early history of agri-culture. Edited by E. S. Higgs, pp. 83–96. Cambridge: Cam-bridge University Press.

k a p p e l m a n , j o h n . 1996. The evolution of body mass andrelative brain size in fossil hominids. Journal of Human Evolu-tion 30:243–76.

k e i t h , a r t h u r . 1925. The antiquity of man. London: Wil-liams and Norgate. [op]

k e n n e d y, k e n n e t h a . r . 1984. “Growth, nutrition, and pa-thology in changing paleodemographic settings in South Asia,”in Paleopathology at the origins of agriculture. Edited by M.N. Cohen and G. Armelagos, pp. 169–92. Orlando: AcademicPress.

k i e s e r , j u l i u s a . 1990. Human adult odontometrics. Cam-bridge: Cambridge University Press.

k ru s k a , d i e t e r . 1987. How fast can total brain size changein mammals? Journal fur Hirnforschung 28:59–70.

———. 1996. The effect of domestication on brain size and com-

position in the mink (Mustela vison). Journal of Zoology (Lon-don) 239:645–61.

k u n z l , c . , a n d n . s a c h s e r . 1999. The behavioural endo-crinology of domestication: A comparison between the domes-tic guinea pig (Cavia aperea f. porcellus) and its wild ancestor,the cavy (Cavia aperea). Hormones and Behavior 35:28–37.

l a h r , m a r t a m i r a z o n . 1996. The evolution of modern hu-man diversity: A study of cranial variation. Cambridge: Cam-bridge University Press.

l a h r , m a r t a m i r a z o n , a n d r i c h a r d v. s .w r i g h t . 1996. The question of robusticity and the relation-ship between cranial size and shape in Homo sapiens. Journalof Human Evolution 31:157–91.

l a r s e n , c l a r k s p e n c e r . 1984. “Health and disease in pre-historic Georgia: The transition to agriculture,” in Paleopa-thology at the origins of agriculture. Edited by M. N. Cohenand G. Armelagos, pp. 367–92. Orlando: Academic Press.

———. 1995. Biological changes in human populations with agri-culture. Annual Review of Anthropology 24:185–213.

l i e b e r m a n , d a n i e l . 1996. How and why humans grow thinskulls: Experimental evidence for systemic cortical robusticity.American Journal of Physical Anthropology 101:217–36.

l i e b e r m a n , d a n i e l e . , b r a n d e i s m . m c b r a t n e y,a n d g a i l k ro v i t z . 2002. The evolution and developmentof cranial form in Homo sapiens. Proceedings of the NationalAcademy of Sciences, U.S.A. 99:1134–39. [op]

l i e b e r m a n , d a n i e l e . , m a u r e e n j . d e v l i n , a n do s b j o r n m . p e a r s o n . 2001. Articular area responses tomechanical loading: Effects of exercise, age, and skeletal loca-tion. American Journal of Physical Anthropology 116:266–77.

l o r e n z , k o n r a d . 1971. Studies in animal and human be-haviour. Vol. 2. London: Methuen.

l o r e n z o , c a r l o s , j o s e m i g u e l c a r r e t e ro , j u a nl u i s a r s u a g a , a n n a g a r c i a g a r c i a , a n d i g n a -c i o m a r t ı n e z . 1998. Intrapopulational body size variationand cranial capacity variation in Middle Pleistocene humans:The Sima de los Huesos sample (Sierra de Atapuerca, Spain).American Journal of Physical Anthropology 106:19–33. [op]

m a r t i n , d e b r a l . , g e o r g e j . a r m e l a g o s , a l a n h .g o o d m a n , a n d d e n n i s p . v a n g e rv e n . 1984. “Theeffects of socioeconomic change in prehistoric Africa: SudaneseNubia as a case study,” in Paleopathology at the origins of ag-riculture. Edited by M. N. Cohen and G. Armelagos, pp.193–214. Orlando: Academic Press.

m e a d o w, r i c h a r d h . 1989. “Osteological evidence for theprocess of animal domestication,” in The walking larder: Pat-terns of domestication, pastoralism, and predation. Edited byJ. Clutton-Brock, pp. 80–90. London: Unwin Hyman.

m e i k l e j o h n , c h r i s t o p h e r , c a t h e r i n e s c h e n t a g ,a l e x a n d r a v e n e m a , a n d p a t r i c k k e y. 1984. “Socio-economic change and patterns of pathology and variation inthe Mesolithic and Neolithic of Western Europe: Some sugges-tions,” in Paleopathology at the origins of agriculture. Editedby M. N. Cohen and G. Armelagos, pp. 75–100. Orlando: Aca-demic Press.

m e i k l e j o h n , c h r i s t o p h e r , a n d m a r e l z v e l e b i l .1991. “Health status of European populations at the agricul-tural transition and the implications for the adoption of farm-ing,” in Health in past societies: Biocultural interpretations ofhuman skeletal remains in archaeological contexts. Edited byH. Bush and M. Zvelebil, pp. 129–43. British ArchaeologicalReports International Series 567.

m o r a l e s m u n ı z , a r t u ro , m a n u e l a n g e l c e r e i j op e c h a r ro m a n , f r a n c i s c o h e r n a n d e z c a r r a s -q u i l l a , a n d c o r i n a l i e s a u v o n l e t t o w - v o r -b e c k . 1995. Of mice and sparrows: Commensal faunas fromthe Iberian Iron Age in the Duero Valley (Central Spain). Inter-national Journal of Osteoarchaeology 5:127–38.

m u l v a n e y, j o h n , a n d j o h a n k a m m i n g a . 1999. Pre-history of Australia. Washington, D.C.: Smithsonian Institu-tion Press. [op]

o ’ c o n n o r , t . p . 1997. Working at relationships: Anotherlook at animal domestication. Antiquity 71(271):149–56.




p a r d o e , c o l i n . 1995. Riverine, biological, and cultural evo-lution in southeastern Australia. Antiquity 69:696–713. [op]

p e a r s o n , o s b j o r n m . 2000. Activity, climate, and postcran-ial robusticity. current anthropology 41:569–607.

p e r z i g i a n , a n t h o n y j . , p a t r i c i a t e n c h , a n dd o n n a j . b r a u n . 1984. “Prehistoric health in the OhioRiver Valley,” in Paleopathology at the origins of agriculture.Edited by M. N. Cohen and G. Armelagos, pp. 347–66. Or-lando: Academic Press.

p l a v c a n , j . m i c h a e l . 2002. Sexual dimorphism in primateevolution. Yearbook of Physical Anthropology 44:25–53. [op]

p r i c e , e d w a r d o . 1984. Behavioral aspects of animal do-mestication. Quarterly Review of Biology 59:1–32.

———. 1999. Behavioral development in animals undergoing do-mestication. Applied Animal Behavior Science 65:245–71.

r a t h b u n , t e d a . 1984. “Skeletal pathology from the Paleo-lithic through the Metal Ages in Iran and Iraq,” in Paleopa-thology at the origins of agriculture. Edited by M. N. Cohenand G. Armelagos, pp. 137–67. Orlando: Academic Press.

r e i t z , e l i z a b e t h j . , a n d e l i z a b e t h s . w i n g . 1999.Zooarchaeology. Cambridge: Cambridge University Press.

r i n d o s , d a v i d . 1984. The origins of agriculture: An evolu-tionary perspective. Orlando: Academic Press.

ro h r s , m a n f r e d , a n d p . e b i n g e r . 1998. Przewalskihorses from zoological gardens: Are they domesticated horses?Berliner und Munchener Tierarztliche Wochenschrift 111(7–8):273–80.

———. 1999. Feral animals are not really wild: The brainweights of wild domestic mammals. Berliner und MunchenerTierarztliche Wochenschrift 112(6–7):234–38.

ro o s e v e l t , a n n a c u r t e n i u s . 1984. “Population, health,and the evolution of subsistence: Conclusions from the confer-ence,” in Paleopathology at the origins of agriculture. Editedby M. N. Cohen and G. Armelagos, pp. 559–83. Orlando: Aca-demic Press.

ro s e , j e ro m e c . , b a r b a r a a . b u r n e t t , m a r k w.b l a e u e r , a n d m i c h a e l s . n a s s a n e y. 1984. “Paleo-pathology and the origins of maize agriculture in the LowerMississippi Valley and Caddoan culture areas,” in Paleopathol-ogy at the origins of agriculture. Edited by M. N. Cohen andG. Armelagos, pp. 393–424. Orlando: Academic Press.

ru f f , c h r i s t o p h e r b . 2000. Body size, body shape, andlong bone strength in modern humans. Journal of Human Evo-lution 38:269–90.

ru f f , c h r i s t o p h e r b . , e r i k t r i n k a u s , a n d t r e n -t o n w. h o l l i d a y. 1997. Body mass and encephalizationin Pleistocene Homo. Nature 387(6629):173–76.

ru f f , c h r i s t o p h e r b . , e r i k t r i n k a u s , a l a nw a l k e r , a n d c l a r k s p e n c e r l a r s e n . 1993. Postcran-ial robusticity in Homo. 1. Temporal trends and mechanicalinterpretation. American Journal of Physical Anthropology 91:21–53.

s h e a , b r i a n t . 1989. Heterochrony in human evolution: Thecase for neoteny reconsidered. Yearbook of Physical Anthropol-ogy 32:69–101.

s m i t h , b ru c e d . 1995. The emergence of agriculture. NewYork: Scientific American Library.

s m i t h , p a t r i c i a , o f e r b a r - y o s e f , a n d a n d r e ws i l l e n . 1984. “Archaeological and skeletal evidence for die-tary change during the Late Pleistocene/Early Holocene in theLevant,” in Paleopathology at the origins of agriculture. Editedby M. N. Cohen and G. Armelagos, pp. 101–136. Orlando: Aca-demic Press.

s p e n c e r , m a r k a . , a n d p e t e r s . u n g a r . 2000. Crani-ofacial morphology, diet, and incisor use in three native Amer-ican populations. International Journal of Osteoarchaeology10:229–41.

s t o c k i n g , g e o r g e w. , j r . 1968. Race, culture, and evolu-tion: Essays in the history of anthropology. New York: FreePress.

s u s m a n , r a n d a l l l . , d a r ry l d e ru i t e r , a n d c . k .b r a i n . 2001. Recently identified postcranial remains of Par-anthropus and early Homo from Swartkrans Cave, South Af-rica. Journal of Human Evolution 41:607–29. [op]

t c h e r n o v, e i t a n . 1984. “Commensal animals and humansedentism in the Middle East,” in Animals and archaeology, 3,Early herders and their flocks. Edited by J. Clutton-Brock andC. Grigson, pp. 91–115. British Archaeological Reports Interna-tional Series 202.

———. 1993. “From sedentism to domestication—a preliminaryreview for the southern Levant,” in Skeletons in her cupboard:Festschrift for Juliet Clutton-Brock. Edited by A. Clason, S.Payne, and H.-P. Uerpmann, pp. 189–233. Oxbow Monograph34.

t c h e r n o v, e i t a n , a n d l i o r a k o l s k a h o r w i t z .1991. Body size diminution under domestication: Unconsciousselection in primeval domesticates. Journal of AnthropologicalArchaeology 10:54–75.

t c h e r n o v, e i t a n , a n d f r a n c o i s f . v a l l a . 1997. Twonew dogs, and other Natufian dogs, from the southern Levant.Journal of Archaeological Science 24:65–95.

t e i c h e r t , m a n f r e d . 1993. “Size and utilisation of the mostimportant domesticated animals in Central Europe from thebeginning of domestication until the late Middle Ages,” inSkeletons in her cupboard: Festschrift for Juliet Clutton-Brock.Edited by A. Clason, S. Payne, and H.-P. Uerpmann, pp.235–38. Oxbow Monograph 34.

t r i n k a u s , e r i k , s t e v e n e . c h u r c h i l l , a n d c h r i s -t o p h e r b . ru f f . 1994. Postcranial robusticity in Homo. 2.Humeral bilateral asymmetry and bone plasticity. AmericanJournal of Physical Anthropology 93:1–34.

t ru t , l y u d m i l a n . 1999. Early canid domestication: Thefarm-fox experiment. American Scientist 87:160–69.

v i l a , c a r l e s , p e t e r s a v o l a i n e n , j e s u s e . m a l -d o n a d o , i s a b e l r . a m o r i m , j o h n e . r i c e , ro d -n e y l . h o n e y c u t t , k e i t h a . c r a n d a l l , j o a k i ml u n d e b e r g , a n d ro b e r t k . w a y n e . 1997. Multipleand ancient origins of the domestic dog. Science 276:1687–89.[cg]

v i s s e r , e d w a r d p . , a n d g e o r g e j . d i a s . 1999. A casefor reduced skin sensation in high latitude prehistoric Polyne-sians. Annals of Human Biology 26:131–40.

w a l k e r , a l a n . 1993. “Perspectives on the Nariokotome dis-covery,” in The Nariokotome Homo erectus skeleton. Editedby A. Walker and R. Leakey, pp. 411–30. Cambridge: HarvardUniversity Press. [op]

w e i d e n r e i c h , f r a n z . 1937. The dentition of Sinanthropuspekinensis: A comparative odontography of the hominids. Pa-leontologia Sinica, n.s., D 1:1–180.

———. 1943. The skull of Sinanthropus pekinensis: A compara-tive study on a primitive hominid skull. Paleontologia Sinica,n.s., D 10:1–291. [op]

w e l l s , l . h . 1963. “Stature in earlier races of mankind,” inScience in archaeology. Edited by D. Brothwell and E. Higgs,pp. 365–78. London: Thames and Hudson.

w i l s o n , p e t e r . 1988. The domestication of the human spe-cies. New Haven: Yale University Press.

w o l p o f f , m i l f o r d h . 1999. 2d edition. Paleoanthropology.Boston: McGraw-Hill.

z e d e r , m e l i n d a . 2001. A metrical analysis of a collection ofmodern goats (Capra hircus aegargus [sic] and C. h. hircus)from Iran and Iraq: Implications for the study of caprine do-mestication. Journal of Archaeological Science 28:61–79.

z e u n e r , f r e d e r i c k . 1963. A history of domesticated ani-mals. London: Hutchinson.

z o h a ry, d a n i e l , e i t a n t c h e r n o v, a n d l i o r a k o l -s k a h o r w i t z . 1998. The role of unconscious selection inthe domestication of sheep and goats. Journal of Zoology 245:129–35.



human domestication reconsidered - semantic …...human domestication reconsidered author(s): helen...

Documents