Variation in maternal care- Between species- Within species

Parent-offspring conflict

MotheringCercopithecines

Baboon mother and infant

Park Ride

Carried

Cling

Nest

Tree

Variation between speciesStyle (park/ride)

The main mammal pattern

(rodents, pigs, ungulates, etc)

Park (nest, branch)

Park + Ride

Ride

Ancestral state unknown

Ross (2001) IJPTarsius

CeboidsCercopithecoidsHumanApes

Daubentonia

Indriidae

Lepilemur

Tree-shrews

Loris

Lorisoids

Galago/oides

Euoticus, Otolemur

Mouse lemurs

Phaner

Varecia

LemurHapalemur

Eulemur

1. Ancestral state = Parking

2. Riding evolved often

3. Riding is maintained

Riding is a repeated primate trait.

Park (nest, branch)

Park + Ride

Ride

Ancestral state unknown Ross (2001) IJP Tarsius

Daubentonia

Indriidae

Lepilemur

Tree-shrews

Loris

Lorisoids

Galago/oides

Euoticus, Otolemur

Mouse lemurs

Phaner

Varecia

Hapalemur

Apes

Cercopithecoids Ceboids

Lemur

Eulemur

Riding: > 4 independent appearances

Park (nest, branch)

Park + Ride

Ride

Ancestral state unknown

Ross (2001) IJPTarsius

CeboidsCercopithecoids

Apes

Daubentonia

Indriidae

Lepilemur

Tree-shrews

Loris

Galago/oides

Mouse lemurs

Varecia

Lemur

Hapalemur

Human

Lorisoids

Euoticus, Otolemur

Phaner

Park+Ride:

> 2 from Park*

> 1 from Ride+

*

*

+

Costs (allometric) of riding, cf. parking:

(1) Smaller home ranges(2) Late weaning(3) Late age of first reproduction

Riding compared to parking:

(1) Same Inter-birth interval(2) Same Growth rate(3) Same Infant size(4) Same Brain size

Retrieving parked infant Arctocebus

So why has riding evolved?

Ho: Improved infant survival

Ross (2001) IJP

Riders: Contact time similar in different species

Mothers carry offspring more when needed

Altmann & Samuels 1992 BES

Kanyawara Field Station (Photo AH)

Mothers are important for survival!

… even when not dead

Mothers are important for RS!

Large group

Small group

Variation within species1. Ecological conditions:

Food availability

Gilgil

Amboseli

Drakensberg

High-quality

Low-quality

% time spent feeding by mother

………… Expected

Observed

Lycett et al 1998 BES

P. c. ursinus Chacma

Harsh conditions:

Infants forage less independently (closer to mother)

Age

% Time

Good habitat

Intermediate habitat

Bad habitat

Twice more independent in a good habitat compared to a bad one !

Lycett et al 1998 BES

P. c. ursinus Chacma

Drakensburg

Harsh conditions:

In harsh environment, mothers work harder.

(infants suckle more)

{ 5x diff.

Good habitatIntermediate habitatBad habitat

Variation within speciesEcological conditions:

Predation Risk

No predation

Some prednMother’s hard work pays!

Variation in maternal care3. Dominance rank / style

High-rank

mothers

carried

less.

Mother’s Style

Laissez-faire Restrictive

Mother’s rank High Low

Infant allowed to leave < 2 months Later

M follows I Rare Common

M joins I Rare Common

M punishes I Less More

M-I contact Less More

Altmann (1980)

Variation in maternal care

Maternal style

Parent-Offspring conflict: OBSERVER’S Perspective

B = Benefit to Offspring(e.g. 10 cc of milk)

C = Cost to Mother(e.g. extra daysbefore next birth)

Age of Offspring

B/C

WEANING CONFLICTAGREED: M CARES

AGREED: M STOPS

B=C

When to wean? MOTHER’S Perspective

B/2 = Benefit to Mother

? ??

B = Benefit to Offspring

C = Cost to Mother

Age of Offspring

B/C

Wean when “rB < C”i.e. when B/2 < C

C/2 = Cost to Offspring

When to wean? OFFSPRING’S Perspective

B = Benefit to Offspring(e.g. 10 cc of milk)

C = Cost to Mother

Age of Offspring

B/C

Wean when “B < rC”i.e. when B < C/2

Wean when “B < rC”i.e. when B < C/2

C/2

B

Age of Offspring

B/2C

Age of Offspring

Wean when “rB < C”i.e. when B/2 < C

“EARLY!!” “LATE!!”CONFLICT!!!

WHY PARENTS AND CHILDREN FIGHT

Parent-offspring conflict

Infant age (weeks)

3030

25

50

Cayo Santiago

(feral, subtropic)

Madingley

(cages, UK)

% total nipple contacts

(attempted + successful) rejected by

mother

Mothers do reject young

Infant age (weeks)

3012

Relative Responsibility Index: RRI

RRI = (% M-I body contacts initiated by infant) -

(% M-I body contacts terminated by infant)

RRI

0

25

50

25

50

I joins and/or M leaves

M joins and/or I leaves

Who’s responsible for declining maternal investment?

Mother’s investment falls

Gelada:

More infant contact during

RESTING SOCIALIZING

than during

FEEDING MOVING

Contact MOTHER

Contact NIPPLE

Infants seek investment mostly when mother is not busy

Infant age (months)

987654321

Re

jectio

ns p

er

min

of

activity

.040

.030

.020

.010

0.000

Context

Feeding

Socializing

Gelada: Rejections occur almost entirely when mother is feeding

No rejections were observed during

moving and resting

Time on nipple

Ventral + Nipple

Suckling time decreases little!

van Schaik & van Noordwijk (1999) Primates

Mothers need to wean early to increase their lifetime RS

Age-specific fecundity Macaques (3 species)

Parent-offspring conflict:

Amount versus Timing

Barrett et al 1995 Anim Behav

PlayFightingAllomotheringLearning

Juvenile relationships

Childhoodin

Macaques

Macaca fuscata

Japanese macaque

Benefits of Play: cf. going to school

Benefit to young: Skills?

Lone play M = F

Play-fighting M > F NHP’s

Play-mother F > M NHPs’

Tool-use F > M Tai, Gombe

Social manipulation?

Mother distracting Infant (weaning)

Learning competition

Early coalitions/relationships?

Benefits of Play: cf. going to schoolLone play M = F

Benefits of Play: cf. going to schoolPlay-mother F > M NHPs’

Benefits of Play: cf. going to schoolPlay-fighting M > F NHP’s

Benefits of Play: cf. going to schoolTool-use F > M Tai, Gombe

Rainfall

% play-time

Economics of play

(1) Benefit

More play when more food

Some primates never play!

Economics of play(2) Cost

Vervets eaten when playing – Red-tailed infant playing at the very top of a fruit tree (Kibale) caught by eagle

Vervet allomothers (captive)

Who?

Juvenile ff 65

(sibs; high-rank)

Adult ff 25

Juvenile mm 7

Adult mm 3

Benefit to mother

Why be an alloparent?Females - nulliparous

*** Practice: improved mothering ** Nepotism: caring for kin * Market forces: care for HR’s offspring (get support in return)

Females - parous (e.g. langurs) * Nepotism * Non-kin: odd

suggesting friendship?

Males - juvenile * Nepotism * Practice mating * Market forces: care for HR’s offspring (get support in return)

Males - adult ** Paternal care*** Mating effort

Wallen et al. (1995) Hormones and Behavior

14

7

0

DaughterSon

Yearling-controlled

proximity to mother

(% time)

Girls spend more time with mother than boys

Rhesus macaque

Wallen et al. (1995) Hormones and Behavior

14

7

0

Daughter

Sons

Yearling-controlled

proximity to mother

(% time)

Neonatal T affects how much time boys spend with mother

T control T T

Rhesus macaque

Lonsdorf et al 2004 Nature

% time at mound spent termite-fishing: girls > boys

Termites per dip

Lonsdorf et al 2004 Nature

Mother’s % dips at given tool length

Daughter’s % dips at given tool length

Lonsdorf et al 2004 Nature

Mother’s % dips at given tool length

Son’s % dips at given tool length

Juvenile relationships: anticipating adulthood

Dominance relations in FB-groups

Juv F Juv M

Juv F Maternal Rank Size

Juv M Size Size

e.g. Pereira, Amboseli baboons

Juvenile relationships: anticipating adulthood

Infant Juvenile Adult

Pereira, Amboseli baboons

0 30 (months) 60

# Supplants received per hour from HR females Female

Male

Juvenile relationships: anticipating adulthood

Juv F Juv M

Challenged by Adult FF YES NO

Supported by Adult FF YES NO

‘Head-flag’ to Adult FF YES NO

“ “ Adult MM NO YES

Non-kin supported HR-FF Juv MM

Pereira, Amboseli baboons

Baboon rules for treating juveniles

Adult FF

Juvenile FF: support their rank

(winner support)

Juvenile MM: dominate as long as possible

Adult MM

Ignore sex/rank (dominate all)

Support possible offspring

Old view New view

Juvenile Passive Active

Juv period Long, to learn Fast growth, risky

Major influences Proximate Ultimate

(experience) (social system)

Quality of life Relaxed Dangerous (>50% die)

23 FF, 2 groups, 240 cases

90% held I’s = higher-rank

F > M

Kin > Unrelated

De Waal 1990 Primates

“Double-holding”:

Play

Play partners

Infants Same size

HR preferred

Juv FF Infants (HR preferred)

Juv MM Juv MM