- Correction: Macaque mating posture is on page 472 in Campbell
- Mating may occur when conception is not possible
- Functions of allomothering:
- Good practice for adolescent females
- Inclusive fitness among relatives
- Mothers need lots of help
- Infant socialization
- Easy adoption if mother dies
- 30Mate choice:
- Female choice (most common):
- Parental investment (Trivers, etc.); often subverts male/male competition,
BUT much variation (Table 30.1 pp. 480-482 in Campbell)
- Solicits male support
- "Rare male" effects
- Protects against incest
- Protects against infanticide
- Maximizes genetic variation among offspring (if multiple partners)
- Male choice:
- by female rank
- by female age (=fecundity)
- by sexual swellings AND/OR behavior indicative of ovulation
- 31Menopause:
- 32Social systems:
- Wrangham's model p. 501 top
- Socio-ecological model p. 503
- Grouping types (p. 505, may vary seasonally or ecologically):
- Multifemale-multimale (most common)
- Cohesive (one large group, maintains vocal or visual contact)
- Fission-fusion (subgroups form and separate repeatedly)
- Community of more dispersed groups that come together less often
- Unimale-multifemale (e.g. Hamadryas baboons)
- Unifemale-multimale (reported in some callitrichids)
- Two-adult group ("nuclear family")— adult pair plus offspring (gibbons, some Atelinae)
- Socially dispersed (noyaux) (some lemurs)
- 34Seed dispersal:
- "Seed shadows" p. 525
- Promotes rainforest diversity (because of omnivorous diets)
- 37Self-medication
- 38Kinship and kinship avoidance— how incest is avoided":
- Dispersal of one sex:
- Female philopatry, male dispersal (most common)
- Male philopatry, female dispersal (sometimes in chimps, bonobos, Atelinae)
- Both sexes disperse; most friendships with maternal kin
- Adolescent females care for younger sibs; often adopt them if mother dies
- Females recognize kins; bonds are lasting
- Mother's status inherited by children, esp. males
- Kin bias—
- Play more with kin
- Cooperate more with kin in food search and exploitation
- Reciprocal altruism greatest among kin— reinforces kin selection
- "Rare male effect" counteracts kin bias ("Don't mate with your former playmates")
- 39Cooperation and competition within social groups:
- Why such strong social bonds among primates?
- Learning through play
- Help in finding food
- Alertness to predators and other dangers
- Allomothering and possible adoption
- Percent of time social:
- Varies among studies (maybe by habitat or by season)
- Highest in macaques, langurs, and chimpanzees
- 40Controlling aggression:
- Appeasement ("bringing peace")
- Dominance status as aggression avoidance
- Degree of control usually low (except: Hamadryas baboons)
- Social units:
- spatially close
- time together
- individual recognition
- communication and cooperation
- reciprocal altruism
- division of labor (by age, also by sex)
- Territoriality and spacing:
- True defense of real estate is rare
- Group distance
- Scent marking in Strepsirhini
- 41Reconciliation and appeasement:
- Important to "make up" and become friends
- Recognize social status
- Appeasement gestures:
- Hold bottom
- Hug or embrace
- Kiss
- Genital touching
- Grooming or gentle touching
- Great variation
- Need for further study
- 42Communication:
- Types:
- Visual: gestures (no displacement);
also body signals incl. sociosexual, age (color changes), facial markings,
individual recognition
- Auditory:
- may reflect aggressive intent, excitement, or distress
- may be a social warning, or a "keep closer" signal ("I am here")
- poosly studied, but repertoire increases among apes
- Olfactory: sexual cycles (less important than in other mammals)
- Tactile: indicates closeness, social bonding; begins with mothers and infants
(Compare Confucius's "five relationships": parent/child, older/younger sibs,
frend/friend, husband/wife, ruler/subject)
- Honest (reliable) signals:
Usually costly to produce, or reliable at lower cost if repeated by same individual;
requires individual recognition for sender to become trusted over time
- Deception:
- Sometimes failure to signal food is punished (by aggression) after discovery
- Habituation to unreliable callers ("boy who cried wolf")— may be context-specific
- Limited repertory: only a few alarms or other signals
(but vervet monkeys distinguish leopards from eagles in alarm calls)
- Origin in infancy; progressively refined (differentiated) later on
- 43Tool use:
- Stones to crack nuts (cebids, macaques)
- Orangutans: twigs or sticks to get insects or honey
- Chimpanzees (and their young): termite tool, leaf sponge, drinking brush
- Making tools
- Multi-part tools: hammer stone + anvil
- Cognition:
- "Theory of mind"
- Oddity
- "Reverse reward contingency":
Select smaller stimulus (e.g., one raisin) to get larger reward (many raisins), & vice versa
even lemurs can be trained to master this;
can also show "mental time travel" into future, e.g.,
choose small quantity of food for
earlier access to water (versus large quantity for delayed access)
- Can learn delayed gratification
- Can learn symbolic substitution (e.g., poker chips)
- 44Social learning and "culture":
- A. Schultz: Primates are (1)Smart; (2)Social; (3)Dependent for long juvenile period
Therefore: social learning, even sometimes culture
- Imitation
- Examples: macaques; chimpanzees
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