Intergroup relations Baboons and Mangabeys
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Transcript of Intergroup relations Baboons and Mangabeys
Intergroup relations
Baboons and Mangabeys
DEFINITION Home range: Area exploited by a group of primates (defended but not exclusively)
Overlap between home ranges
Territory: Area exploited and EXCLUSIVELY defended by primates
No overlap betweenterritories
Home range / TerritoryNon-territorial primates defend a clumped, desirable food source, such as large fruiting trees.
Ex: capuchins, red howlers, baboons, mangabeys, great apes
These species require large home ranges, relative to their day ranges (distance travelled in one day). They cannot keep intruders out of their home range at all times.
No overlap in territories. Possible to defend EXCLUSIVELY a territory if the day range is roughly the equivalent of the radius of their home range.
Ex: gibbons, ring-tailed lemurs, tamarins, dusky titis, red-tailed monkeys (?), blue monkeys (?).
Strier 2003; Cheney 1987, In Primate Societies
Home range / Territory
Relationships between home range and other factors:
• The home range increases with species body weight
• Range increases with group size, both within and among species.
• Terrestrial primates have larger home ranges than arboreal primates
• Frugivores have larger home ranges than folivores
Rodman 1999, Ann. R. Anthropol.
Intergroup relations are clearly aggressiveaggressive,
although sometimes they are not.
For instance: red-tailed monkeys in Kibale NP
(Uganda). Sometimes they are, sometimes they
are not (pers. obs.).
Intergroup relations
Intergroup relations
Problem of definition: Cheney and Seyfarth (1977)
defined it for baboons as any approach of one
group within 500 m of another. Inappropriate for
primates with small home range / territory.
Cheney 1987, In: Primate Societies, 267-281. Chicago
UP.
This raises the problem of estimating encounter
rates.
Intergroup dominanceWhen home ranges overlap extensively, and are
not defended, the aggressive defence of a
resource (like a fruiting tree) may be costly.
-> Avoidance of other groups (Intergroup
Dominance).
Cheney 1987, In Primate
Societies
Intergroup dominance often determined by group
size, and the number of adult males in that group
(e.g. baboons, macaques). Not common when
territorial.
Sex differences ?Since femalefemale reproductive success appears
limited primarily by energetic and nutritional energetic and nutritional
constraintsconstraints, female grouping patterns are
influenced by food distributionfood distribution.
Cheney 1987, In Primate
Societies
Thus females are predicted to be more aggressive females are predicted to be more aggressive
toward femalestoward females of other groups than toward males,
or males toward males of other groups.
Sex differences ?
• In those primate species characterized by female female
dispersaldispersal, females tend NOTNOT to participate in intergroup encounters.
Cheney 1987, In Primate
Societies
• In contrast, males are hostile toward males are hostile toward
members of other groups, especially other members of other groups, especially other
malesmales. Such hostility seems to be related to the defence of females.
• Ex: chimpanzee, gorilla, red colobus.
Sex differences ?• In those primate species characterized by male male dispersaldispersal, females participate aggressivelyaggressively in intergroup encounters (almost all Old World monkey species).
• Female antagonism mostly against other females, sometimes against males. Related to the defence of food !
Cheney 1987, In Primate
Societies
• Males antagonism mostly against other males. Related to the defence of females !
• Ex: langurs, macaques, baboons, geladas.
Q. 4: WHY DEFEND A TERRITORY?
Strier 2007
Hypothesis:
Territorial behavior (defense of an area) depends on “economic defendability”.
“Economic defendability” depends on a low cost of defense (long day-range: small home-range)
Gorillas: NO
Vervets: YES
Siamang Chimpanzee Orangutan Gorilla
Relative size of core area
Distance traveled per day in relation to size of core area
Yes No No NoCore areas defended?
Wrangham (1979) Soc Sci Info
Diameter = d
Average day-range (path-length) = r
ID = Index of Defendability
= r/d
Core areaor
Home range
ID < 1 ID > 1
Cercopithecus (aethiops, mitis, ascanius)Callicebus (moloch, torquatus)
Colobus guereza (Dunbar)
Hylobates larSymphalangus syndactylus
Presbytis entellus (Yoshiba)
Lemur catta
Propithecus verreauxiIndri indri
Lepilemur mustelinus
Pongo pygmaeus
MiopithecusPapio ursinus
Lemur fulvus, mongoz
Saimiri oerstediAlouatta seniculus
0Territorial
NON-territorial
Presbytis entellus (Jay)
Macaca mulatta, radiata
Cercocebus albigenaTheropithecus gelada
Alouatta palliata
Colobus guereza (Oates), badius
Pan troglodytesGorilla gorilla
Papio anubis, cynocephalus
E. patas
Baboons and MangabeysBaboons and Mangabeys Share a recent common ancestor Part of the Afro-papionins :
savannah baboon, drill and mandrill, gelada, and hamadryas, mangabeys
Confusion between two groups of mangabeys : Cercocebus and Lophocebus are paraphyletic Now Cercocebus Mandrillus Theropithecus Lophocebus
Papio
Another confusion = taxonomy of savannah baboons From the same genus or not? Yes (Groves 2001). No (Jolly 1993)
Overall approx. 12 species of Afro-papionins
Mangabeys - LophocebusMangabeys - Lophocebus
L. aterrimus
L. albigena(feeding on figs (F. sansibarica)
Mangabeys - CercocebusMangabeys - Cercocebus
C. torquatus(self-grooming)
C. galeritus(feeding on yellow palm fruits)
GeladasGeladas
T. gelada(xeric habitat)
Hamadryas Hamadryas baboonsbaboons
P. hamadryas(hybrid zone with P. anubis)
Savannah Savannah baboonsbaboons
P. anubis(eating meat: gazelle)
Savannah Savannah baboonsbaboons
P. ursinus P. papio (AM following AF-oestrus)
P. cynocephalus (AM protecting infant)
Baboon social organizationBaboon social organization
Stable troopsStable troops >10 females>10 females > 5 males> 5 males
Henzi & Barrett (2003) Evol Anthropol
Anubis, olive
Yellow
“Savanna” baboons Hamadryas baboons (one-male units)
Savanna baboon social Savanna baboon social structurestructure
F-F: Strong alliances, dominanceF-F: Strong alliances, dominance F-M: Friendships (increases F F-M: Friendships (increases F
reproductive rate)reproductive rate) M-M: Dominance, some coalitionsM-M: Dominance, some coalitions Intergroup: Xenophobia +/- Intergroup: Xenophobia +/-
territorialityterritoriality
Female-female dominanceFemale-female dominance= stable, based on mother’s birth = stable, based on mother’s birth
rankrank
Laikipia anubis. Barton and Whiten (1993)
Agonistic relationships among females have few reversals.
Laikipia anubis. Barton and Whiten (1993)
High-ranking (female) baboons eat more
Females care about rank reversals between more than within families
Okavango (Bergman et al. 2003)
Female dominance hierarchies don’t always predict success
Cercopithecus mitis Blue monkeys, Kakamega (Cords 2002 Behaviour)
Cercopithecus mitis
Blue monkeys, Kakamega (Cords 2002 Behaviour)
Amboseli
Silk et al. 2003
But: sociality can be more important than rank (in promoting RS)
Chacma baboons, South Africa, Barrett & Henzi 2002, Behaviour
Grooming time is a measure of friendship.
But, it also responds to interest of infants.
Female-male friendshipsFemale-male friendships
Defining ‘Friendship’ between Female and Male.
(1) Spatial proximity.
Use ethograms to score dyads (range 0-20).
For most FF, top M scores ‘10’For most FF, top M scores ‘10’; the rest scores <3.
(2) Grooming.
Record all grooming bouts.
For average F, top M = 65% of her grooming65% of her grooming.
(3) Defining a ‘Friend’.
‘Friend’ = high score on BOTH proximity & grooming.
Characteristics of F-M ‘Friendships’Characteristics of F-M ‘Friendships’
(1) Approaches by Female.
To Friends: routine (feed, groom, travel)
To non-Friends: submissive, present, appease.
(2) Duration.
Similar age (often start as adolescence)
Could be lifelong.
(3) Distribution.
FF: 1-2 M Friends (FF sharing a M were also friends).
MM: 0-8 F Friends (high-rank MM had more F friends).
Benefits of F-M ‘Friendships’
(F1) Protection.
>90% of MM protecting a F were Friends.
(F2) Baby-sitting.
Intolerant of infants except Friends’.
(M1) Paternity.
Increased present and future probability of paternity.
(M2) Agonistic buffers.
Friends, especially infants, can be used as social buffers.
Male-male relations:Male-male relations:Dominance !Dominance !
Old “friends”
Agonistic buffering
Intergroup relationshipsIntergroup relationships
Xenophobia +/- territoriality
Chimpanzee Baboon
Philopatry Male Female
FM bonds None Strong
FF bonds Weak Strong
MM bonds Strong Few
Chimpanzee / Savanna baboon social structure compared
“The study of social behavior is no substitute for the study of social relationships.”
Robert Hinde (1981)