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Institute of Biology, Section for Ecology and Evolution

DAILY PATTERNS OF GROOMING BEHAVIOUR

IN CHACMA BABOONS (PAPIO URSINUS)

Internal supervisor: Associate professor, DSc. Torben DabelsteenExternal supervisors: Dr. Guy Cowlishaw

PhD stud. Alecia Carter & Harry Marshall Institute of Zoology, Zoological Society of London

A test of the biological market theory

Tsaobis Baboon Project - Namibia

TSAOBIS BABOON PROJECT

• Guy Cowlishaw

• Ecology & behaviour – Desert-adapted baboon population

• Since ~ year 2000 • Central Namibia – Tsaobis Leopard Park

• 2 PhD’s + 6 volunteers

PROGRAMME

Introduction

Methods

Results

Discussion

Conclusion & perspectives

Introduction

• Care for/cleaning skin, fur, feathers etc.

• Behaviour in many animals

• Especially among primates

• Auto- vs. allo-grooming

• FunctionHygienicStress reducingSocial

• Cost Time for other activities Vigilance

WHAT IS GROOMING?

Introduction

WHY GROOM OTHERS?

Altruism between relatives • Kin selection theory (Hamilton, 1964)• Factor of relatedness, r• Hamilton’s rule: rB > C

Cooperation between non-relatives• Reciprocal altruism (Trivers, 1971)• Three conditions:1) B (receiver) > C (donor)2) High probability for future encounters3) Receiver and donor remember each other -> behaviour reciprocated

Does the same behaviour need to be reciprocated?

Not necessarily!

?

Introduction

THE BIOLOGICAL MARKET-THEORY

• Primates-> social complex group-structure

• Many social interactions

• Seyfarth (1977), Nöe & Hammerstein (1994), Henzi & Barrett (1999)

• Grooming as currency1) Can be reciprocated for itself2) Can buy other ”services”

• Grooming can be exchanged for:1) Access to infants2) Support during aggression3) Tolerance during feeding

• The market is dynamic- Supply and demand- The value of the service/commodity- Individual characteristics

Introduction

Rank diff.

Chacma baboons

• Females stay in natal group -> matrilines

• Adult males emigrate

• Strong linear dominance hierarchy

• Males fight for their rank

• Females inherit their rank from their mother

Alpha-maleAdult malesMatriline 1 ( -female, daughters/sons)αMatriline 2 (…)Matriline 3 (…)…Lowest ranking female

Socially complex group-structure

Relatedness

Social bond

Sex, age, rank, sociality

Sex, age, rank, sociality

Introduction

• Grooming buys tolerance -> Rank diff. btw. groom pairs greatest in the morning

• Family and ’friends’ exhibit tolerance -> groom more in the evening

• Tolerance’s value matches payment -> Greater effort in the morning when rank diff. is great

• Feeding competition raises the value of the tolerance

• Lowest ranking + social + older individuals negotiate more tolerance

It is not random, who grooms who at what time of day

PURPOSE, HYPOTHESES & PREDICTIONS

Methods

STUDY AREA• Swakop river• Two habitat types

Semi-desert

Riparian woodland

Methods

THE BABOONS

L (n=24) J (n=36)

• Two groups

• Habituated to observers

• Individually identifiable

L sleeping cliffsJ sleeping cliffsJ & L sleeping cliffsWater holesCamps

Methods

DATA COLLECTION

• May – November 2009

• Follow groups from dawn to dusk

• Training period

• 1 h. focal observations

- Behavioural state

- Dominance interactions

• 10 min. focal observations

- Events: Approach/retreat

- 5 m. distance

• Ad libitum dom. interactions

Methods

DATA SET

1 groom bout = groom activity btw. same pair; pause of max 10 seconds

• Individual + groom partner -> repeated observations

• Several groom bouts in the same observation

-> Data not independent

• Many predictors

• Interaction-effects

General linear mixed model (fixed + random effects)

Methods

MODELS

4 model categories

Model 1: Rank difference

Model 2: Relatedness

Model 3: Social bond

Model 4: Groom effort per bout

Groom pair of

1) all types of individuals

2) only adult females

Choice ofpartner

?

?

Methods

PREDICTORS & STATISTICS

• Time of day, where the groom bout occurred

• Rank difference

• Relatedness

• Social bond

• Feeding competition

• Initiator’s rank, age & sociality

• Interactions – all variables with time of day

• Two statistical tests

1) Likelihood ratio test

2) Markov chain Monte Carlo test

Model with only the important factors

Only if not the response-variable

Results

HOW MUCH TIME IS SPENT GROOMING?

• 1780 hours focal observations (1 t. focal obs.)

• 1844 groom bouts

• Juvenile og adult females spend most time (14%) – sub adult males least (3%)

Forage

TravelRest

Allo-groomingDrinkPlayAuto-grooming

All individuals (60)

Results

DO PAIRS HAVE A HIGHER RANK DIFF. IN THE MORNING?

YES!

• Estimate±SE: -0.008 ±0.004, P<0.01

• Not for adult female pairs

• Relatedness correlates positively (P<0.001)

Effect of other factors?• Feeding competition: No

• Rank, age og sociality: No

Time of day

Rank difference

Model 1: RANK DIFFERENCE

Results

DO RELATIVES GROOM MORE LATER IN THE DAY?

NO!

• BUT … more in the morning

• Estimate±SE: -0.008 ±0.004, P=0.09

• Also among adult female pairs

Effect of other factors?• Feeding competition: No

• Rank, age og sociality: No

Relatedness

Time of day

Model 2: RELATEDNESS

Results

DO ’FRIENDS’ GROOM MORE LATER IN THE DAY?

NO!

Effect of other factors?• Feeding competition: No

• Age og sociality: No

BUT…• Adult females: Daily pattern

affected by initiator’s rank, P<0.05

Only when the groom bout’s

initiator is the dominant

Model 3: SOCIAL BOND

Late

Early High rank

Low rank

Strength of social bond

Time of day Rank

(dom

.)

Results

GROOM PARTNER CHOICE

• The prediction about rank difference was correct!

• Mornings: Pairs with high rank diff. og relatedness

• No effect of feeding competition,

rank, sociality og age

BUT

• Within adult female pairs - effect of rank

-> when the dominant initiator’s rank is low

-> grooms with subordinate ’friends’ in the morning

?

?Model 1-3: RANK DIFFERENCE, RELATEDNESS & SOCIAL BOND

Results

IS THERE A GREATER GROOM EFFORT EARLY IN THE DAY?

NO!

• But… greater later in the day

• Estimate±SE: 0.07 ±0.03, P<0.01

• Higher rank, less effort

Effect of other factors• Feeding competition: No

BUTThe daily pattern depends on:

• Relatedness, when initiator is subord.Time of day

Initiator’s groom effort

18 min.

2.5 min.

55 sec.

3 sec.

Model 4: GROOM EFFECT

Results

GROOM EFFORT, WHEN INITIATOR IS SUBORDINATE

Depends on relatedness (P<0.05)

• Close relatives -> greatest effort in the morning

• Non-relatives

-> least effort in the morning

Influence of other factors?• Large rank difference (P<0.001)

• Higher rank (P<0.05)

• Older (P<0.05)

Greater effort

Late

Early Closely related

Not related

Groom

effort (subord.)

Time of day Relat

edne

ss

Model 4: GROOM EFFORT

Results

GROOM EFFORT

• Generally smaller groom effort earlier in the day

• No extra effort in the morning with high rank difference

• Higher rank, smaller effort

• BUT - when initiator is the subordinate

-> greater effort when rank is higher

• No effect of feeding competition

• When the subordinate grooms a close relative

-> greater effort in the morning

Model 4: GROOM EFFORT

Discussion

WHY GREATER RANK DIFFERENCE IN THE MORNING?

• In accordance with the biological market theory

• More beneficial to negotiate tolerance earlier

• Why not negotiate tolerance the whole day?

1) A subordinate also has parasites!

2) Has costs

3) Risk of aggression

The choice of who & when is important!

Model 1: RANK DIFFERENCE

Discussion

WHY NO DAILY VARIATION IN RANK DIFF. IN AD. FEMALES?

They do not choose each other strategically during the day• They do not negotiate tolerance with each other

• High competition for adult females

The value is high – it pays all day long• Tolerance is returned over several days

Model 1: RANK DIFFERENCE

Discussion

Tolerance is also negotiated between relatives?• More beneficial in the morning

• Lower risk of aggression

• Better ’rate’

Greater benefits of getting groomed in the morning?• Higher stress levels?

• More ecto-parasites?

WHY DO RELATIVES GROOM MORE IN THE MORNING?

Model 2: RELATEDNESS

?

WHO IS CHOSEN IN THE MORNING?

Close relativeHigh rank difference

Close relative

Model 1 & 2: RANK DIFFERENCE & RELTEDNESS

Discussion

WHY NO DAILY PATTERN IN ’FRIENDSHIP’?

• Tolerance is not negotiated between ’friends’

• More and closer social bonds -> higher fitness

BUT!

Why does a low ranking adult femalestart to groom a subordinate ’girlfriend’more in the morning?

• Competition for females/risk too high

• Females trades with e.g. males in the morning

• Special strategy: Use ’girlfriends’ to get groomed?

Model 3: SOCIAL BOND

Discussion

WHY DOES FEEDING COMPETITION NOT HAVE AN EFFECT?

• Feeding competition does not vary considerably

• Dispersal behaviour? Optimal exploitation of available food sources?

• Competition for partners -> Not an unrestricted choice!

• If tolerance is negotiated -> less aggression

Discussion

WHY IS THE GROOM EFFORT LOWEST IN THE MORNING?

• Does not support the hypothesis

HOWEVER

• Highest ranking individuals need to groom least

• Higher rank difference greater effort for the subordinate

• At the bottom of the hierarchy less effort especially limited in time?

ALSO FOUND

• Both high relatedness and rank difference in the morning

Groom bouts shorter in the morning (found!)

Mornings could be a hectic time

Model 4: GROOM EFFORT

Discussion

EFFECT OF RELATEDNESS ON GROOM EFFORT

• Generally lower effort in the morning

BUT…

• The daily pattern depends on relatedness, when the initiator is subordinate

WHY?

• Great effort strengthens a social bond important after a night?

• Tolerance negotiated between relatives Beneficial in the morning

• Help a close relative removing parasites + reduce stress

It pays for a subordinate to spend extra time in the morning grooming a close relative

Model 4: GROOM EFFORT

Conclusion

WHAT DID I FIND?

Grooming in the morning

• High rank difference

• High relatedness

• Low groom effort

It is NOT random who grooms who, when and for how long

In accordance with the biological market theory! tolerance is negotiated with both dominants and relatives the baboons structure their choice in an optimal way during the day

New hypothesis - ’Groom-less-with-more’

Perspectives

’GROOM-LESS-WITH-MORE’ IN THE MORNING?

• Optimises the benefit• Bet on more individuals -> lower risk of losing all effort

Perspectives

FUTURE STUDIES

• MISSING LINK! Grooming in the morning Tolerance later?

• What type of pair trade with each other in the morning?

• Higher stress levels and more parasites in the morning?

• Higher groom partner shift rates in the morning?

THANK YOU!GENERAL SUPERVISIONTorben Dabelsteen (DK)Guy Cowlishaw (UK)Alecia Carter (AU)Harry Marshall (UK)

STATISTICSRoger Mundry (GE)Thorsten Balsby (DK)Gösta Nachman (DK)Michael K. Borregaard (DK)Karina Banasik (DK)

DATA COLLECTIONAlecia Carter (AU)Harry Marshall (UK)Katherine Forsythe (AU)Rebecca Bodenham (UK)Will Symes (UK)Jenie Iles (NZ)Will Birkin (UK)Hannah Peck (UK)

INSTITUTIONSInstitute of Biology, University of CopenhagenInstitute of Zoology, Zoological Society of LondonDesert Research Foundation of NamibiaNamibian Ministry of Lands and ResettlementNamibian Ministry of Environment and Tourism

OTHERSSolveig Walløe HarpøthNana HeslerMikkel Bjelke Kristiansen

FINANCIAL SUPPORTCarlsberg’s Fond for Studenterrådet ved Københavns UniversitetDitlev Marcussen Buch og hustru Maren Buch, Baltzergaard StiftelseFriedrick Wilhelm Frank og hustru Angelina Frank’s MindelegatGreve A. Brockenhuus-Schacks Legat for den slesvigske ungdomGrosser Wilhem Rackwitzs LegatHotelejer Anders Månsson og hustru Hanne Månssons MindelegatKolding Gymnasiums VennerKøbenhavns Kommunes Legat for uddannelse mv.Købmand Jørgen Sørensen og hustru’s fondOticon Fonden Studiehjælpen Valdemar Shiøtts MindeThorkild og Thea Rosenvolds Legatfond