Fish and Wildlife Research 13

Biology of North American Tortoises

Edited by R. B. BuryD.]. Germano

UNITED STATES DEPARTMENT OF THE INTERIORNATIONAL BIOLOGICAL SURVEY

Washington, D.C.• 1994

DAVID J. MOIAPKA 161

Neonates: Mieain 8 LiDks~ the Life IIl8tories ofNorthAmerican'!brto.....

DaWi J. )Iorafb

Cali(omi4 Stale UaiN., llaIabIpamzz.Departmat ofBiolqa

Qnon, CtJli(omitJ 90747

Abiita....EaBaad.........«l,..o1d)..tbe__~IifiI.....af'tMNorthAmIrica~(GapINrw).Neaaa_baw~JQ1k...._hiPermetabolic,... PI*iD cIeauuIdI. aDd naporatift ..... dIaD MaI&~. SaaaJl tort.oIIeIdiI'Ir by ......... <......... aad lIMn rabaI& beq abIIl Hr aDdbealliww) rr....__ af'tIaIir lilterr.aiJ.y(tM...,..l. N l aadjuftDile....1dDIIiIJDaTbe bytbeldulta<........., Le..dmallaafromtbat1Pial~ ot&anaadaD of ..... ad,.,.. ......... ill~ oramaJkiIed oftano....... a.poetIc ..". be..m...... ill the1'NDI. Ll8t hiatmy modela of tarCaiIII ant OIl raw Jan of of""adultI, wtJic:b an iDadIquta &0 cbInc:tIriIe tbIIe .... with ..au.. immature....adloqli&t....ofadu1t:LAmocW • PI"'"tobeJpaplaba tbeclulMicDdureof pncipitata.l &lid~ ill ....... populatioDL AacordtaI to • bet-bIdaiaImodel,tbe~ ...of""'(~)aad.,......~,.)orlliaiJarlile tobelilDUM;batlbe~ottlle...ad__oftt.ecbIJemiI appcriaDlddiflil8&bt~haw"""" bat OCtile...or otmaA'!-..)didtmtle N...-.l tGI1IDUeI twicetheweilhtor ..,... The fila toI...... ita 1lIIYbe.,..,... to thenlatiwIJ banb, ftriabIt oftenutriallifa.

a:. ........ Bet bed..... --.IIMICW. ........tal .... 00pMrut. batcbliqtortoiIu, repnduc&i.. dbrt.

Ega aDd. neoutes (<1 ,... of ap) are the • 8l. 19M). 'lbrtoi.MI do DOt have COIIC8Dtra1ied.leut-well·doclJmeDt8cI.... ill the liw. aCNorth ......arlJDCbnDo-........ofbItebHnpAmerican tortDi8a n.. miui..,liDb CCIIIlpi."O- that facDitata _diM of DIItiDI in _ ...mile ef!'ortt to cbarac:teriu life b.iIt:.orYe fill" mod- (Bendricbcm 1981; Mortimer 1982). ~watereliDe uui m.n·linl t.ort:oiIeL~ tWd Itudie8 ..,.ud turtIM an between theM two utalllNS;rnealed a ac:an:ityor.... lMOIIateI. udjUftDilM t:bIir t8rremialneR"'are uaualIynot fill' tram(Bura- 1978i DoqJua 19'18; Judd. aDd McQueen IIbore«100m>uulaftlDiDncapiable nIIIt:rata1980; SbieIda 1880; Berry uul 'nImtr 1888; Die- of Mec- aDd IUd ban CBmR IIlCl Barbourmer 1986; Adat It & 1988a; 'Ibm 18M; WilIOIL 1972; Coqdon et al. 1983: Wilbur mel~

illltt~!:1

ii~;

!~i~tt:t

:iti

i~;~

ir!i

jl~_

~l!l

!tl~

iuiua

tUiU

Ull;

_In

i111

i!J~n!

~Jhl

·if

~f-!ei

:a.

Uii

~l'l-rI-

{•

1<'\-1

.,.01

1:aII

&~,

mi

rr.(i

1!..

1:wa

•s.t

I~

~I

'~..~

~"ll'lltJ

i~'li

lil

i

I 5 =

I i I I,

ffr

r'"

~J

~0

[i

SiS

.-I

G11

·~

II

tIi~

.....iJ

1I

!f

.I

,~

fI

il'ii~

rI~

£

~Ill

lloill

llfll!

'~I.

tI-

r1.."

'";l~

8:1!liln

tJli

~ril

liif

irgut

II'.ftfl~

ii~,

utilI

UII.Ji

fl;-,

ilif

hl3i.I

Iltd

""III

!IIif

s'r~n

811

IIIi

!i

(,

JI~

rilt

lHJ"~

oIf

II-

!1srU

g!~~

.~e.r

~i

_~11

i·CD 2­

as ....~

~Z

...t

tS"

i1f

s-·-

f~

Jil~vtl.f

~if~

fJ~~

glli

~

1~~!~l

lil;'I

!i~iIJ

!lflff

lll~tl

iff!

'iiEIE!I.IK~il.ffJJtl

uti

~~l...-

-~!illi·1~1.~:tia~~i-I~~.

D~g

ills-is

s-I11

-·t

11II,"i

fll-l-:

Cif!~

~I~i

(11~"

"J

Sit

gIt

I&

fitl

!r-

-!~li~i!j~~ifl~i~1

rll~

:~lf

JIII

~h

.hff

ihh

lUfJ

f,hJ

h~q

ffh

PJ

.I

wiDtar. But. ill a few ..... thm'e may be • I8CCIDdaDd aipihat iftwval betwIeD pipiDa of the ..IbeU aDd actual........&om the DIIt(GibbaaaaDd NeJ80n 1178). TbiI pheaomeDon hu a1Io beenDalBdiD tbe......._ tarde (CarwIta ccuwcto;Chri8tea8 1990),ADotberUlliqlae~of1flUDllDeODa_

DUlYbe theDeUtralpHoftheirMmaacbltbatfoatersfermenting 0( mp.ted lIIIUftIheI • in batcbJiDa'~ ipono mo"er 198U). IDa-tion ~ JIOil arfeces to oc:cur ill 1MlOD&&al desert tonoiIesthat in the ran ill the )(oj... DesertClLJoyDer, CalibDiaStateUDi~DomiapezBiJbI. Canoe. pII'ICIDII1 COIDIIlvnbtion).

JUftDi1e Bo1Ian tom.... (G./14~)c:natIld~ tnilI at the opeD.iDp of IhDrtburrowa UDder __ sbnib Clnopies (8IpedallyOpruatio cactwI) into open a....,18D8I'81lY Ikirt­iDa the periphery ofedible V818f;ation ('Ibm 1994),Soae oftbele tzoIiJs may apoIIIt the youq tortoiAto~ microc1imatic streu, or biIh~orpuhaocut.aaeoua water loa. Ifoweftr. their hiPIUl'f'Ee.to-wlvme ratio may allow ueonates to ereficfeIltl,y t.hermonIaJate in cool ea'riroDmeD.ta.NeDDatelipowi~_..earJi..witbiD the calen·dar year aDd within a IiDIle clay than their adultcounterpartI <'l\IrMr et Ill. 1986). The early emer­puce D supported by obeenatioDa of EIYPfian~ (7atado iIeinmanni)-a amall.med spe­cies that uhibita early seuonal. behavior aDdmuch winter utivit.y-4iom Iarul'. Nepv Desert(Geft8n..MeDdelaIlDlm 1988).

2803,000

43415-'1

1(27)

4.0.8brittle4030

10-80

2010-1513-16

6031

3022

2803.000

U1220101'27818.3

pueiuaeDt2820

60-615rare-e.cwtatiY..?

1ao8

'1WIIeI.CamperitaDaf~~or....~-wJadNortb.Am8ricantortoi8u (GGP-w .pp.). Data Jaqely fromCoaadm .... GibbaDI (1186, 1981, 1180) aDdQenneDO Q8N}.

of bacteria and ftmgi to tbe ,aJk IDUI CWeiDbeq1984),

When the absorption of the yolk 1DUI is cam­pleted. the emerpnt tortoise (aboui 40 DUD lmt8>extended its lencth by about 201(, from fetal di­mensions in the .. Ihe1l <D. Montka, 1lDpU­lisbecl data). Nuclear mapetic imapry indicatesthat even several mcmtba~ b.tc:binr the ,JG1k Punt:tionol and ComporatirJe MorpholDllYmus_.remains recopizabl. intemaJly (M. A.Joyner. Ca1if'ornia State U~_ DomiDIuez The Iize, shape. auul kiDatb of the ...ta1Hilla. Carson, penoraal commUDiadou). Belidual IIheJl help addnsa .... aucb .. minimal viableyolk lipid could provide a wiU ranpofoptioaa lor 11K"andpucIomarpbamainsmaU-siucladulta.the timing (Be8fO".Jjty) or 8JD8l'I'IIlC8 (GibboDll The deveJopmem ofmezbnwn..width in cheIo­and Nelson 1978). Dlau ia 1imit8d by tt- caaatninta or the ....

Evidence of oV8'l'WiDterinl by embt)Oii or IUtO- pe!w.(CaDa*maDdGibboDa 1985,198'7l.Arepee­nates of desert tortoi8es (GopMru ",im1 in aioD of..width to body me (after CaDa*m adNorthAmerica is limited (Grant 1936; Lllekmbleb Gibbou 198&) pnJjeeta aD..width of 15 DUD tor1982). SimilarlY. NODateI of the Jeopud tortoise the amall_ North American emJdid, a.mm~(Gfot:h«o1utpartltW.). a lup tvnoiM oftemperate ~. which is a freahwater tarde aboutsoutbem Africa. may spend 4'12 ..,. betwwn ... 90 DUll CL (Carr 1152; EmItadBury 19'77). Thedeposition aud. the _puce from ....(JIC- actual..wicWI ofc. """'1IbetP ill 14-16 DUllq,- 1969). In IIIOlIt eues, tbe loDe iDterval D <Erut azul Barbour 1972). The pelvia ill tortoi8eIaplained by a Ioor dia,... in~ in IDQ'baftnolVlldatrca:tandpropoI't:iaDatoaebtne

W92-t461 fWR 131 C1Ip. t51 MInjb 1P1 +2M41 PZ '"100M 1P3 1·lH4

"

a pit that elnatea the IbeIl tal' 0ftI'lud. 1DG98I. IlouIul DO UIII1:JIia that ida*iliecl the 10wer 1imitaoftbe..wicltb in~ In the .pecIded Cape.toiIe CHCIIJIOPIM ....) ofMrb, tile 1UUl..width illO.llDIIl<8o)caUaDClBoaquiu 1188>,wIDch it ...... than tt. width·of ... ill other"'v'injclaof~tbe....."(81mmCL).The.,widdl it abom 1.3 __ larprinB. .......tbua inc.~. '!be larp to bepoaibl...... the poRariar lobe al the feJuleplutroaainHomopaan kiDItic uui abdaatlICl foro9ipoaitioa. Similar pauift abducdoa of thexipbiplaatroa bu been~ otthe ...eQeet orthe North Amerieaa tertDiIIe, GopMru 6riPa­dim (Bole and Judd 1991). A pIuticity oft:bl..has a1ID bMn f'ouDd iDN....<RoH 1982; I'cIia1963). and the pli8biIit)'aftbe parebalentegsbe1lmay be UDique in teatudiDid8 (Ewert 1985).

The pater width altha tortoiII8 ...may be arespoDM to selection for a Iaqer necmaal tort:oiIein Ii8I'l"eItrial enviroDm..ta. I'or example. thereare poIitive relatiou betlll86il iDCNUId lIUni~­

Ihip aDd 1arpNUed... aDd Jarpr-1iztMl hatch­linp in cbehmi'DI (Swmllmd 8Dd Coe 11'19:h­ert 1.; WIlbur aDd Marin 1888) ad ipanidliIarda CFfilJW*lii aad BobI_D 1978; Sm.w aDdHu.yl99O).SeleetioDmayaUlofavorap8tVJQltresene with which aewbom tortoias can meetW1C8l'tain~CQIlditioaa.

DiIIimI b1 may DIOD&tal tDrtoiIea beliDllOODaftwemelpuc:a fivm the Deltflbm 18N)aDdcom­pouadI the .... fbr limb ItiniiiItb. Lupr ,...are prabIb1J &lao subjedad to !ewer .... hIDsmaJl pndatms (rodent&, .... reptilee, bin!I) andhaw a Iowr surface.tD-9OhuDe ratio, wbic:h n­cluceI the rate atwater __

1IMMer. terreItrW lifeaJaoe iudlquatetoapIaia the adaptatioDaat1lqv UIIlbatch-Iinp.Boxturtles(pnUl~)ueat6uwtriAlpoup ofeDlJdida bu.t have..n ....<OaiW.)aDdnermatll Cmus about 7 r> libothereIIlJdld turtle,(CoaaQaDaDd<libboI.l885.l98'1; DondFudX8lth1880). their cbeIt relatiwe. Herbi~ ma-.dlridity or Ubi_t. aDd ro.orial behaw.- may de­JUDd .... &om GopIIIru ......_. which havepea-m&II (about 30 r> tba AeODUeI ofaqaaticturtla

IDCNMIClIiM app8l'8lltly c:ontributeI flo .. It-~ ofaD inlDVirauuntl with lICUI:e

low-6ber (Demmat azul Van SoeH 1985).

DAVID J. KoIlA.PKA 166

For aampJe. diet~ jzuticad that daertipaDa~ dtnalU) are herbiwrouatbraapoat ute ()Iaata ud Nq,y 1987). NlODIIwJliaaN8 II8IIl to .u.et .....n pJat.... that areJaw ill Iber ClODtIDludlDllY '-ciJitate mee:blnicalma-tiaD a4cbaricaJ _irnflation offooda. SomeD......Jaquatic~ (nebu tbe 2C).mm-Ioa,~ 01P.utllnV- ......) aN .. herbi­".... (Balbl.,DD ..VaQlbu 1911>. '1bII DeeM­

11171D8CImdCl8J eIIbrt for MtiDc the hiIbly IbrouICCIIItat ofmolt tIIftItrial plaDta ratber thaD her­bi9aryitMlffawn.larprliaaoftortoiBeDeODaieI.

Lazpr...aDCl.....oftMtudini.da~be.. c:buMeIIr..that an fiDel by MJectioDoper""_ tbemmmon......ofthe tortoiIeLOateo1oIioal UIl~l cJw.ten sua­pat that tMtudiDidI are dIriftd from tha be­tiprid faDDb' ofturtlu., pouibly aDCHton aftheAaiaD bax turtle (pnaa Cuoro; Ga&eyaDd Mey­Jan IB88). RelaUwly1uIaaDdbrittle ahalled. ....are • IJDivenal characteriRic of taatudjDidi uultMir baUprid etelton (E. KoIl, Butam nn­DOia UDiwrait); Urbau. penoaal coauauaica­tioD). PhyklpDeti~larp .... aDd DeODateIan IYIlplUomorphic: to t.o1'toiIeI and may be'ViewBd ..Bad traits. ,

The ph_aDD ofhetmucbrony ill reptilee baaalia beeD1araab"~Acti&reD.ti.al ODtopDy

atbody puts occurs in smaIl-sized lizards. iDcluci­m.1DicrcItaiidI (PnIcb 1980) aDd ICiDridi (Griffth1991). c.n.p.ea aDd pIutmn kinaa'i are eommOllIn uaaD.-IIiIerl .,.. or c:beloniana CRicbmcmdlBM), oftbMe Itate8 JD8¥ be pudnmor-pbic (..... JdJaMf. ma,y be a ftmdamfttal cIiarac­teriItic ofJQaDI fDrtDiIII).

I haftDOt fiNDd a redadioDmthe enal apertuJeof DeOND' a1fdar tartlea~. IC'I'ipIcI ...,.,.,l. limiJ·r to a wl\1Jltar,f nBpOIII8 in jUftllile~(O.~aDdG...izii)tbatreducu tb8 aalpp bebaMll posterior maraiDa ofthe carapace ad~ AdDwnwanl addudioGofb paMedar caraplCllI8JII8 til be mOlt napoD­lib....tUkiDemI I~ that tba IlDIItradioDZ'ICi1aI the ........ laP by .. much u 5C)(I, inG.~ aDd. OCCUI'I tbrouch the seventbyarafUte.Ro....., tbe e UtmNl!81 medgni..Corthe 0IIIl&nctiDD. ia UIIbawD. )IIIZ'tly ...... theclneIoJIIUDtal ...., of tortoiI. baa beaDJarael7 delcriptift rather tbul bilJl"4riwni':8l andmnftaed to tba Bwopeu.,.,.<Ewert 1985),

wtZ·l46 , fWIt n I c.. 151 MInIra '" 402M41 P2 "10+1/'3 '.1M'

. ~.

· -------------

168 FlsBANDWlLDur& RBSBARcH 13

Molt IZU1l tortoiIeI alIo exhibit abell kiDeIi.,eepedaJly in the poRarior plutron (Pritdwd1979). Not all of tbeR reported kius••• are uecea­uriJ.J or ttDtirely pIUIdamarpbic. 'l1Ie 01IIII$ ofeua­pMe kiNlillate in the CIIltoI8D1 atAlrH:aD hiDp­backed tortoi.e. (pnu. KiIaiz)w) and theprGIftIIift tJaibt1_ aad. fla1;tenj." ofthe Afriampmeeb tortoiae(j(~... tom;'i) ... DOtparaiDllftDioua with aimp1a paedomarpbic upleN_tioD8 (ObIt 1988). P8rbapI the ODtopDy ofld"Nilin tbeIe taD provieJel little or DO evideDce of~erochroD~

Sinrilady.hiDpaiDlCIID8emydid~(7Irrrap­CM ad CuDnI) IIJd ill mud turtI_ (lriwM'ltea'Did81have DOt ... attribu:tlld. to jUV8DiJe ardiMJWIeDta.SoftIIbeU turtles (trioD.Jchids) nlpneeDt a specialNdud:ion ofBbeU aaiftcwtinn that lead to p1utralt1apa that may be p88damorphic cbaraden. Someshell tJaihiJity may be a aeemdery (pIeiDtropic)~ of small Ilia III jUftDi1es ucl smallspeci8s. autppeontnu:t:ioDImayreduce the dam-... fram pecIrinc 8Dcl 1I'iDg attacb by m..nbirds. rocleme. end iDwcti The J....... ofxiphiplaatnm ki....~ permit oviPMiticm of1arp .... in adult femiJ. of smallipeciel CBoIeand Judd 1991).

GopMnu AI eubIpecieI of G. polyp1wnwa (Wer­muth and Merteu 1961>. Studies ofmoleeuJlr p­DIItia (Lemb 8& al. 1989) aDd sheD. marphometric:s(Germano 1993) indicate that weU~t.edpopulatiou of G.,.,..;zu eDIt. Northern aDd_tbml popaladoDsufG.~.ape­~ jueniJeI. di&r in carapace eolor CMontka1981), SjmiJlrly. juftDi1e deeert tortoiae8 in theM.qjaftDelertpoerallyhaveputerretioa oflhelldepth to IeDpb. IDDI'8 mid IDd c:ontrutinc cara­peel coloration. and more IDgU1ar or eYeD dentatemaqiDal....oftbeeuapacetbanjuwnilesiD theSoDonDDeIert()(.A. JoyD8r, CaliforniaStateUni­~.1Iit& DomiDpa HIlls. Cuaoa, IIDCl D. Moratb.1IDpubHebed data), Like the epiny turtle CHeoem,sqinGm),a batapridtromSoutbeaatAaia. tortoiIesin the Mojave DeIert teDd to have their IlDIUlarIIlalIiJuU ndw:ecl early in ODtopny {Obst 1988>­Thus. it may be delirab1e to develop a dielDOIIiI of....tortoiaeI (GopMru) based. on variation aDdcWfenmces in juveDile characteristics

Population Ecology

The recn1iillumt or necmata is a key to under­standin. the local distributicma of tortoiulI. 1001-

Systematics term tl"eDdsoftortoiaedeDsitiell. andcaaual factarathat limit the co1oDiel. However. there are fewdataon ncruitmeDt of North American tortoieea (Qer..

RePmal varirm.ta aDd cryptic~ of North JD8DD 19M). Ace or size cia... are needed. mAmerican emydidaand trioDyc:bida are u.euUydis- recoaatructputrata andepiaad..ofrecruitmellt.tinpisheclmon easily from juftllilM thaD. from UDfortuDately, the S\ICCUI rates of emerpneeadu1!J. DefiDiDc chuacteriatica are ofteD variable (relative to total cIepoIited lIP> aDd. IW'Yiwnbipor obscure in adults ofcloIely relat.ecl1lqUaZ tar- of D80D81:ea and juveDile8 may require dec8deB oftIe.. but the colon BDd pUterDII of'juftllile turtles ot..: ,aticma or iJmofttiw breakthraaPa in datatacilitlte identiticatian (CcmaDt; 1978). For eum- ptberiDr.pIe, the Cuatro 0 ....... IIDftaheJl turtle (ApaIone Aa maD,Y U 10 yean ofnprodw:tlve e8brt mayspi7aiferu ater) wu deIc:ribedlarplyfnllll diapoe- be required for sw:eeutUl population rec:ruitmeattic cbarac:ten that were oaJy reliable in j11ftllile8 in GopMrva polyp/wIIJw (Anffimberg and IV8nOIl(Webb 1960; Manfta 19?'1). 19'79; lAnders at al. 1980) ... in enviIoDmIm1:I

The iderltifleadoD ofdiapoetic ch8rader _tell with relatively Itable dime_ aDd biab wptatiwof JOUDI tortoiIeI baa been c:DIJ8traiMd heea.. produdi'fity beca..BOIDe iDdividuali and popula­(1) neooates are poorly k:Down aDd rareb' obIened tiau of this .ped_ may skip reproduction for onein the field or pnIIeJ"Qd in c:oD.ectioD.r, (2) the 1bur ormare yean. Two species oft0rt0iBe8 (G.~lII*iee of GopIatrw are allopatric (n«Inciq the adG.~)occar ill North Am.namDeed lot ripaua eIi.poetic byw); aDd (3) DO ... dellIia, where IUCCIlIfbl ncnitmeDt it probIbb'.... orany North American 1IartIUe haft been iDfnquentbecaueofwqndictableweatberillariddIIcribed. eaept in GlUt attempt of cIauir:YiDI an eDvirvnmeati CKoratb 1977. 1982; Germano

W92-146 I FWR 13I~ 15/""/ Pl ~1Z""1'2 6ot0.94/PJ 7·12....

1994), Arare ..of8Il'Viromamtal CODditimw maybe uces"ry fir the recruitment of tortaiIM- TheabIeIa or rarityofju.....u. ill populatloDa fbr 1-2decade8 IDAY DOt iDdicate recruitment failure inarid enYirolmleD&a. .Tbelaap9ityof~ tlmeCOMtnintaof

a&udies by p-aduate stada.ta, aDd. DlcoI:udsteDtftmdiDl of ..-..reb CDlllbine to make loag-termecolaIical m,di.. rue. Comparative life historielof all four~ epec:ieI may require 20-30years betbn pnci8e model, for rec:ruitmeDt can hevalidated withc:arrent techDoJoBy aDd. approecbet.

Neonates haft u IIWlY u 3 timas the .-tiDemetabolicrat.oI...3-,..-.old~""'(N'"and Bradley 19'14), aDd the dietIuy needa of ne0­

nates are twiee that ofadult tortoiIa (1n, ftl'IIUB

ft,proteiaCODtent;AdMtetaL 1989b)aDdem,dida(~; Parmenter udAvery 1990), NeoDa_presumably have biIh"demand. Cor water' and zw.trieDtl8w:h u calcium <EIque aDd Peters 1994).

Neon-ta) dietary cIem-ndl"may be qualitatiwlyUDique u well. For upmple, DeDIUltel l6fIG1III.ipIIIG <Tro,v l.984a. !984b) have to aeqaire ap­propriate IOil microtlora ad iDpR 8dult.. forefBcient fermeDtat10n ofcell in the hiDd liltofthe Deon.... There a1Io to be a tFjpiftcantrole for such fermeatiDl auerobes in GopMnupolYPMmra CBjomdal1987). The bual metabolicrates are at least ODe order of JDIIIDitude lower intortoi&eB thanin m-mmlls ofsimil.rDIUI (Prouerand Brown 1968), '!be aurfac:e lldivity of adulttortoises may be ODly 1-2'11 oftbeir yearly activityeN. and Medica 1988;AdeK et aL 1889.).

'Ibrtoilel may aIIo haft Jup NMI..- ofblad.­der water (Nagy and Medica 1986) aDd storedcaIori. in tissue (liver), wbU:h maybe ph)'JlioloP­cal factors that buffer enY'iroDlllental stn...sora. These stores may provide a latent period ofleveral yeal'l between 1IDSUitable periocb anddemOll'8Pbic: respcmI8I in tortoises. Perbape acutegrowth riDp can be wred to document whethertortoises in strea perioda <I.,., drouahte) aremerely surviWli (DO arowth> or IJ'OWiq sliPtlYbued partly on resenea (Germano 1988, 1994).

Rec:ruitmeDt may also be tb8 key to cIetea lIIiDincwhether a population is within the~capec­it1orim eDViroDment. WhendemoIraPhicdatan1yheavily on recorda of the adult ag. or siz.daises. there is little bMia to estimate dynamiccbaraeteriatics .pec:iaJly recnDtment. Criteria of

DAVID J. MolWl'KA 167

~ nprodud:iDn, aDd coborta (ace) mayal80 be UMfdl indicators of the miDimum caft)'iDIca~Alt:boalb these ePimason are more CDIII­

pis tIumsimple Dumhen (e.l-. estimated density).tbey may be ucuoratIaDd ildbrmative me&BUr'M oftrenu. Some incticatan may b. inltructive:(1) blood ...... caD d8fiDe the atate of health()Ionfkaetal.1986); (I)81'D'.1 iDerementi ofeheJl~ can jDdjate the lIowth of jUftlliles (Oer­IIUIDO 1992); (3) the prlt..... 01' relative abundanceofjuveDile col-nel may be nideIu:e of recruitment(AdeBt tit; aL 1989a); (4) the pr..-e ofhetcbJinpmaybe evideDceofIUCCIlIIdbl repnldartiOD; aDd. (5)pafI-bleproteiD.c:ah:ium.JIUICrOIlutrieJlt8, andmi­crahabitata <e.&-, friable IUbstratel) indicate re­8OUl'C8S for DeODlt.el BDd juveDile tortoiIes.

AModel ofRecruitment inChaotic Environments

Natural enviromlumtl may have chaotic proe­.... that do DOt & a 1iaear or invariable coune ofeventl azul thUi have UDpreclictable outcom...Tbeee chaM IlUld.ela haft already heeD UMful fbr!rimulatiDg dispenal and popuJatioD deuaitin ofarthropods (BupU et 111. 1991). Recently. Lieber­muaDdMorafb Cl988)fouDdtbatphysical facton(steep slope, abeeDee ofan alluvial substrate, playaborden) ljmitM! the occwleaee and deDIitiee ofG.~buthmdDOOODIIistmtpredictorsofather bebitat variables. The patchy d1dributiiaIlof BolIOD tDrtai.- in a deMrt enviromDeDt·manc:Ja.ly reMlllbJes cbaaa model. than simple JiDeargrsdieDtl.

1b ap)-iD the patchy cUmibutian oftort.oilea, IdeftIopecl a eb80I maclel Cor recruitment, mach likethe ....,....- dispenal model (Brown end Gib­lOB 1983) that~ lacal weather paU:emIfor the spatiallC8~of pulive propquIM or......... ctilIpnaL Rather than ICatter wPeDeWreproductiveUDitI. the --.theI'paU:emltbem­....... ecatter unpredictahly across a landRape oftDl1iaiBe demes that are relatively IItIIbJe in positionaDd reproductfDD. In the model. the local environ-~.~~d~of ~_..or....)tbatumally prodvce IID811clu~ oflarpeas (n.. W) fJ9V1 year. neD when nutriticmaln8DIJRII are ICIIDt (1UnuIr et al. 1986).

W92-146 f FWR U / Olp. 15/ MoIaftra 1PI 4-2M41 P2 "'0441 Pl 7.12....

."...

JII:fjfJ11IJliliJrJrifi}i~IJI~iIIIJfjiJlilfli.!lfJI11~

ie.-[;;Uh~all

ii;~

~-IJ

iutt

JuUr

it!~

hhJr

jiH

I I,~

.;ni~:&nJ~!lhn~:

tH!B[:;!I'ffHi~iiH

;i;nu

;I t:

~flj

llfl

~irl

:li!

l~fl

lr"~

fll~

E!:!

llll

ll!I

~'ll

Iiii

!!ii!.

fiiHIHHliHU;HI~inIH!unih

~JrJjt

~1!

llrl

~~=r

il~f

lili

~ilrlli~lii~ll~

l:bhu

i!lon

Jduh

h!H

JI·H!fd~d>'.;

~I~

lllf

!ltl

l~tallol.;I!~f~lfll~j~;I~gl

~Il!

I..

I.:

1fI

.ItU

~fB;

II.II

_:I

I"U

(.

ffh~

IIr1 ,I'

'l,fI

·111,II

'"~i

I~ill

"i~~f

U'i

~f.~ifll~

hef

,t~f

'1I,;~in

~'"

f I • rt'

~f~l

fl·ftri~~

1IIIJ~!~fl

f~11

'f':

Iif

f11

'1.,1Jl

i

S'~iI~

1':

'I:..t!

,.g

~so

,IiIrI'

I.s'

11~[Ir

.r1rI

!l.i

r·1

I

IRlln

1,_til

Ii.'

j!1!I

~,II

IIt r' II

fUfli

fsr:

IIli.JI

I'~

··ItI

~I

Ii

170 PI8II AND \VW)un RI:SB.t.,RCH 13

Aelmowlecfrments

u.cl G. Adat fOr mmmentl on thIt manWlCript.Muah ~ tbia Ie..... 8IplICiaDy the compuisoD. of~ and teltUclinids, refl8Cta the intIwtDC8 ofL Vltt aDd ........uata nwIeate ill IDa falll989heqIet.DlcJID' 1IIIriP·~ UDi••1ityatCalifbrDia. LollADpla, apri,)'"B. Aver.Jt B. Ben,D, ad C. Pe­tenon. I tIumk J. Btmlnclu, S. Papedla.. aDdH. Peck aDd tor tac:bnial impauvemmt or theIII'DU.mpt. AD rapGDlibility for the preaenteclerran ad. opiniDDI ..... atlre1y with me.

Cited Literature

Brown, J. H., and A. C. Gibson. 1983. Bio ph~

. . Mosby Co., St. Louis, Mo. 643 pp.Buhlmann, K A., and M. R. Vaughan. 1991. Ecology of

the turtlePseudemysconcinna in the New River, WestVirginia. Journal of Herpetology 25:72-78.

Burge, B. L. 1978. Physical characteristics and patternsof the utilization of cover sites used by Gophe1'U8agassizii in southern Nevada. Proceedings of the De­sert Thrtoise Council 1978:80-111.

Carr, A. 1952. Handbook of turtles: the turtles of theUnited States, Canada, and Baja California. Com­stock Publishing Associates, Ithaca, N.V. 542 pp.

Christens, E. 1990. Nest emergence lag in loggerheadsea turtles. Journal ofHerpetology 24:400-402.

Conant, R.1975. Afield guide to reptiles and amphibiansofeastern and central North America. Houghton Mif­flin Co., Boston, Mass. 429 pp.

Congdon, J. D., and J. W. Gibbons. 1985. Egg componentsand reproductive characteristics of turtles: relation­ships to body size. Herpetologica 41:194-205.

Congdon, J. D., and J. W. Gibbons. 1987. Morphologicalconstraint on egg size: a challenge to optimal egg sizetheory. Proceedings of the National Academy of Sci·ences 84:4145-4147.

Congdon, J. D., and J. W. Gibbons. 1990. The evolutionof turtle life histories. Pages 45-46 in J. W. Gibbons,editor. Life history and ecology of the slider turtle.Smithsonian Institution Press, Washington, D.C.

Congdon, J. D., and D. W. Tinkle. 1982. Reproductiveenergetics of Chrysemys picta. Herpetologica38:228-37.

Congdon, J. D., D. W. Tinkle, G. L. Breitenbach, and R. C.van Loben Sels. 1983. Nesting ecology and hatchlingsuccess in the turtle, Emydoidea blandingii. Herpe­tologica 39:417-429.

Demment, M. W., and P. J. Van Soest. 1985. Anutritionalexplanation for body-size patterns of ruminant andnonruminant herbivores. American Naturalist125:641-672.

Diemer, J. E. 1986. The ecology and management of thegopher tortoise in the southeastern United States.Herpetologica 42:125-133.

Diemer, J. E. 1992. Home range and movements of thetortoise Gopherus polyphemus in northern Florida.Journal of Herpetology 26:158-165.

Diemer, J. E., and C. T. Moore. 1994. Reproduction ofgopher tortoises in north-central Florida. Pages 129­137 in R. B. Bury and D. J. Gennano, editors. BiologyofNorth American tortoises. National Biological Sur­vey, Fish and Wildlife Research 13.

Doroff, A. M., and L. B. Keith. 1990. Demography andecology of an ornate box turtle (7errapene ornata)population in south-central Wisconsin. Copeia1990:387-399.

DAVID J. MORAFKA 171

Douglass, J. F. 1978. Refugia ofjuvenile gopher tortoises,Gopherus polyphemus (Reptilia, Testudines, Testu­dinidae). Journal of Herpetology 12:413-415.

Eglis, A. 1963. Nesting ofparrot beaked tortoise. Herpe­tologica 19:67-68.

Ernst, C. H., and R. W. Barbour. 1972. 'furtles of theUnited States. University of Kentucky Press, Lex­ington. 437 pp.

Ernst, C. H., and R. B. Bury. 1977. Clemmys muhlenber­gii (Schoeptn. Catalogue of American Amphibiansand Reptiles:204.1-204.2.

Esque, T. C., and E. L. Peters. 1994. Ingestion ofbones,stones, and soil by desert tortoises. Pages 105-111 inR. B. Bury and D. J. Gennano, editors. Biology ofNorth American tortoises. National Biological Sur­vey, Fish and Wl1dlife Research 13.

Ewert, M. A. 1985. Embryology of turtles. Pages 75-267in C. Gans, F. Billett, and P. F. Maderson, editors.Biology of the Reptilia: development, 14(A). JohnWiley &Sons, New York.

Ewert, M. A., and J. M. Legler. 1978. Honnonal inductionof oviposition in turtle. Herpetologica 34:314-318.

Ferguson, G. W., and C. H. Bohlen. 1978. Demographicanalysis: a tool for the study of natural selection ofbehavioral traits. Pages 227-243 in N. Greenberg andP. D. Maclean, editors. Behavior and neurology oflizards. DHEW Publication (ADM) 77-491. NationalInstitute of Mental Health, Bethesda, Md.

Fischer, R. U., F. J. Mazzotti, J. D. Congdon, and R. E.Gatten, Jr. 1991. Post-hatching yolk reserves: paren­tal investment in American alligators from Louisi­ana. Journal of Herpetology 25:253-256.

Gaffney, E. S., and P. A. Meylan. 1988. A phylogeny ofturtles. :Pages 157-219 in M. J. Benton, editor. Thephylogeny of the tetrapods, Volume I: amphibians,reptiles and birds. Systematics Association SpecialVolume 35. Clarendon Press, Oxford.

Geffen, E., and H. Mendelssohn. 1988. Home range useand seasonal movements of the Egyptian tortoise(Thstudo kleinmanni) in the northwestern Negev, Is­rael. Herpetologica 44:354-359.

Gennano, D. J. 1988. Age and growth histories ofdeserttortoises using scute annuli. Copeia 1988:914-920.

Gennano, D. J. 1989. Growth and life histories of NorthAmerican tortoises (genus Gopherus) with special em­phasis on the desert tortoise (G. agassizii). Ph.D dis­sertation, University of New Mexico, Albuquerque.183 pp.

Gennano, D. J. 1992. Longevity and age-size relation­ships of populations of desert tortoises. Copeia1992:367-374.

Gennano, D. J. 1993. Shell morphology of North Ameri­can tortoises. American Midland Naturalist: 319-335.

172 FISH AND WILDIJFE RESEARCH 13

Germano, D. J. 1994. Comparative life histories ofNorthAmerican tortoises. Pages 175-185 in R. B. Bury andD. J. Germano, editor. Biology of North Americantortoises. National Biological Survey, Fish and Wl1d­life Research 13.

Gibbons, J. W., and J. L. Greene. 1979. X-ray photogra­phy: technique to determine reproductive patterns offreshwater turtles. Herpetologica 36:86-89.

Gibbons, J. w., and D. H. Nelson. 1978. The evolutionarysigniflcance of delayed emergence from the nest byhatchling turtles. Evolution 32:297-303.

Grant, C. 1936. The southwestern desert tortoise, Go­pherus agassizii. Zoologica 21:225-229.

GrifRh, H. 1991. Heterochrony and evolution of sexualdimorphism in the fasciatuB group of the Scincidgenus EUmeceB. Journal of Herpetology 26:24-30.

Hassell, M. P., H. N. Comins, and R. M. May. 1991.Spatial structure and chaos in insect population dy­namics. Nature 353:255-258.

Hendrickson, J. R.1982. Nesting behavior of sea turtleswith emphasis on physical and behavioral determi­nants of nesting success or failure. Pages 53-58 inKA. Bjorndal, editor. Biology and conservation ofseaturtles. Proceeding of the World Conference on SeaTurtle Conservation. Smithsonian Institution Press,Washington, D.C.

Jacques, J. 1969. Hatching and early life of mountaintortoise. African Wildlife 23:96-104.

Judd, F. w., and J. C. McQueen. 1980. Incubation, hatch­ing and growth of the tortoise Gopherus berlandieri.Journal of Herpetology 14:377-380.

Lamb, T., J. C. Avise, and J. W. Gibbons. 1989. Phylo­geographic patterns in mitochondrial DNA of thedesert tortoise OUrobates agassizii), and evolutionaryrelationships among the North American gopher tor­toises. Evolution 43:76-87.

Landers, J. L., J. A. Garner and W. A. McRae. 1980.Reproduction of gopher tortoises Gopherus polyphe­mus in southwestern Georgia. Herpetologica36:353-361.

Lieberman, S., and D. J. Morafka. 1988. Ecological dis­tribution of the Bolson tortoise. Pages 31-46 in C. J.McCoy and D. J. Morafka, editors. The ecogeographyofthe Mexican Bolson tortoise (Gopherus flavomargi­natus): derivation of its endangered status and rec­ommendations for its conservation. Annals ofCarnegie Museum 57.

Lincoln, R. J., G. A. BomaU, and P. F. Clark. 1982. Adictionary ofecology, evolution and systematics. Cam­bridge University Press, Cambridge, England.298pp.

Linley, T. A., and H. R. Mushinsky. 1994. Organic com­position and energy content of eggs and hatchlingsof the gopher tortoise. Pages 113-137 in R. B. Bury

and D. J. Germano, editors. Biology ofNorth Ameri­can tortoises. National Biological Survey, Fish andWildlife Research 13.

Luckenbach, R. A. 1982. Ecology and management ofthedesert tortoise (Gopherus agassizii) in California.Pages 1-37 in R. B. Bury, editor. North Americantortoises: conservation and ecology. U.S. Fish andWildlife Service, Wildlife Research Report 12.

MacArthur, R. H., and E. D. Wilson, 1967. The theory ofisland biogeography. Princeton University Press,Princeton, N.J. 203 pp.

Macartney, J. M., P. T. Gregory, and M. B. Charland.1990. Growth and sexual maturity in the Westernrattlesnake, Crotalus viridis, in British Columbia.Copeia 1990:628-642.

MacMahon, J. A. 1988. Warm deserts. Pages 231-264 inM. G. Barbour and M. D. Billings, editors. NorthAmerican terrestrial vegetation. Cambridge Univer­sity Press, Cambridge, England.

Mautz, W. J., and K A. Nagy. 1987. Ontogenetic changesin diet, field metabolic rate, and water flux in theherbivorous lizard Dipsosau7Us dorsalis. Physiologi­cal Zoology 60:640-658.

Morafka, D. J. 1977. A biogeographical analysis of theChihuahuan Desert through its herpetofauna.Dr. W. Junk B. V. Publishers, The Hague, Nether­lands. 313 pp.

Morafka, D. J. 1982. The status and distribution of theBolson tortoise (Gopherus flavomarginatus). Pages71-94 in R. B. Bury, editor. North American tortoises:conservation and ecology. U.S. Fish and Wildlife Serv­ice, Wildlife Research Report 12.

Morafka, D. J., R. A. Yates, J. Jarchow, W. J. Rosskopf,G. A. Adest, and G. Augirre.1986. Preliminary resultsof microbial and physiological monitoring of the Bol­son tortoise (Gopherus flavomarginatus). Pages 657­662 in Z. Rocek, editor. Studies in Herpetology, 1985Third Annual Symposium of the Societas EuropaeaHerpetologica.

Mortimer, J. A. 1982. Factors influencing beach selectionby nesting sea turtles. Pages 45-52 in K A. Bjorndal,editor. Biology and conservation of sea turtles. Pro­ceeding of the World Conference on Sea Turtle Con­servation. Smithsonian Institution Press,Washington, D.C.

Naegle, S. R., and W. G. Bradley. 1974. Oxygen con­sumption ofthe desert tortoise in relation to size andage. Journal Arizona Academy Sciences (Supple­ment): 17-18.

Nagy, K A., and P. A. Medica. 1986. Physiological ecologyofdesert tortoises in southern Nevada. Herpetologica42:73-92.

Obst, F. J. 1988. Turtles, tortoises, and terrapins. St.Martin's Press, New York. 231 pp.

Parmenter, R. R., and H. W. Avery. 1990. The feedingecology of the slider turtle. Pages 257-266 in J. W.Gibbons, editor. Life history and ecology of the sliderturtle. Smithsonian Institution Press, Washing­ton,D.C.

Pianka, E. R. 1972. r- and K- selection or b- and d-selec­tion? American Naturalist 106:581-588.

Pitchard, P. C. H. 1979. Encyclopedia of turtles. T.F.H.Publications, Inc. Neptune, N.J. 895 pp.

Presch, W. 1980. Evolutionary history of the SouthAmerican microteiid lizards ('teiidae: Gymnophalmi­nae). Copeia 1980:36-56.

Prosser, C. L., and F. A Brown, Jr. 1965. Comparativeanimal physiology. 2nd Ed. W. B. Saunders Co., Phila­delphia, Pa. 688 pp.

Richmond, N. D. 1964. The mechanical functions of thetestudinate plastron. American Midland Naturalist72:50-56.

Rose, F. L., and F. W. Judd. 1991. Egg size versus cara­paee-xiphiplastron aperture size in Gopherus berlan­dieri. Journal of Herpetology 25:248-250.

Rose, W. 1962. The reptiles and amphibians ofsouthemMrica. Maskew Miller, South Africa. 494 pp.

Shields, T. A 1980. Amethod for determination ofpopu­lation structure and density of the deserttortoise. Proceeding of the Desert 'Ibrtoise Council1980:151-155.

Sinervo, B., and R B. Huey. 1990. Allometric engineer­ing: an experimental test of the causes of interpopu­lational differences in performance. Science248:1106-1108.

Snell, H. L., and C. R Tracy. 1986. Behavioral andmorphological adaptations by Galapagos land igua­nas, Conolophus subcristatus: water and energy re­quirements ofeggs and neonates. American Zoologist25:1009-1015.

Stearns, S. C. 1976. Life-history tactics: a review of theideas. Quarterly Review of Biology 51:3-47.

Swingland, I. R, and M. J. Coe. 1979. The naturalregulation of giant tortoise populations on AldabraAtoll, Indian Ocean: recruitment. PhilosophicalTransactions, Royal Society London B (Biological Sci­ences) 286:177-188.

Swingland, I. R., and M. W. Klemmens, editors. 1989.The conservation biology of tortoises. Occasional Pa­pers, International Union for the Conservation of

DAVID J. MORAFKA 173

Nature and Natural Resources (WCN) 5. Gland,Switzerland. 204 pp.

'Ibm, J. 1994. Microhabitats and use ofburrows ofBolsontortoise hatchlings. Pages 139-146 in R. B. Bury andD. J. Germano, editor. Biology of North Americantortoises. National Biological Survey, Fish and Wild­life Research 13.

Troyer, K. 1984a. Behavioral acquisition of the hind gutfermentation system by hatchling Iguana iguana.Behavioral Ecology and Sociobiology 14:189-193.

Troyer, K. 1984b. Diet selection and digestion in Iguanaiguana: the importance of age and nutrient require­ments. Oecologia 61:201-207.

Turner, F. B., P. Hayden, B. L. Burge, and J. B. Robert­son. 1986. Egg production by the desert tortoise (Go­pherus agassizii) in California. Herpetologica42:93-104.

Webb, R. 1960. A new softshell turtle (genus 7Honyx)from Coahuila, Mexico. University ofKansas ScienceBulletin 40:21-30.

Weinberg, E. D. 1984. Iron withholding: a defenseagainst infection and neoplasia. Physiological Review64:65-71.

Wermuth, H., and W. Mertens. 1961. Schildkroten, krok­odile, bruckeneschsen. Gustav Fischer Verlag, Jena.422 pp.

Wilbur, H. M., and J. P. Morin. 1988. Life history evolu­tion in turtles. Pages 387-439 in C. Gans and R B.Huey, editors. Biology of the reptilia: defense and lifehistory 16(B). A. R Liss, Inc., New York.

Wilson, D. S. 1991. Estimates of survival for juvenilegopher tortoises, Gopherus polyphemus. Journal ofHerpetology 25:376-379.

Wilson, D. S., H. R Mushinsky, and E. D. McCoy. 1994.Home range, activity, and use of burrows ofjuvenilegopher tortoises in central Florida. Pages 147-160 inR. B. Bury and D. J. Germano, editors. Biology ofNorth American tortoises. National Biological Sur­vey, Fish and Wildlife Research 13.

Woodbury, A M., and R Hardy. 1948. Studies of thedesert tortoise, Gopherus agassizii. Ecological Mono­graphs 18:145-200.

Wright, S. 1982. The distribution and population biologyof the gopher tortoise (Gopherus polyphemus) inSouth Carolina. M.S. thesis, Clemson University,Clemson, S.C. 74 pp.