Primatology 3

somatic growth and starvation

slow somatic growth reduces risk of starvation - immatures can cope with periods of seasonal scarcity.

ecological risk aversion hypothesis

1. juveniles less efficient foragers

2. juveniles stay near conspecifics to avoid predation

3. thus, they experience high levels of

needing-to-learn

correlation b/w brain size and age at first reproduction because essential skills are learned during developemtn

slow life history = opportunities for socialization and long-term relationships

in mammals, offspring usually reach adult-level skills before maturity

but, in baboons, immatures are lesse fficient iwth difficult to extract resources

Many species keep growing until shortly before the onset of reproduction which suggests that the timing of maturity is limited by time to reach adult body size

3 hypotheses for the protracted juvenile period

1. social skill development

2. needing-to-learn

3. ecological risk aversion

hypotheses in primates for increased encephalization? how about for humans?

primates: ecological intelligence and cognitive buffer hypotheses, social intelligence and machiavellian hypotheses

human: cultural intelligence hypothesis, expensive brain framework (2% of body weight, 20% of energy consumption)

bugger brains = greater risk of concussions and obstetrical dilemma

what is cognition

ability to perceive, memorize, and process information about the social and ecological environment

relationship between neural anatomy/brain size and cognition is contentious

ecological intelligence hypotheses - nonhuman primates

ecological intelligence - ecological challenges in food acquisition selected for large brains; focused on diet features and complexity; locating, remembering, and accessing food sources;

there is a relationship between frugivory and brain size; there is no relationship between brain size and extractive/non-extractive foraging technique

across mammals, primates have a more complex diet and bigger brains, so there could be an example

social intelligence hypotheses - NHP

social intelligence - bigger brains coevloved with increasing complexity of social interaction

positive relationship between brain size and sociality; have to keep track of individual identity, group membership, kinship, dominance, alliances

cognitive buffer hypothesis - NHP

predicts large brain size allows animals to adjust in response to environmental conditions; emphasizes resource availability and seasonality; difficult to predict food should select for enhanced learning and memory

frugivores have larger brain size than folivores

mirror self recognition

do animals recognize themselves?

asian elephants, dolphins, orcas, great apes, and magpies all do

theory of mind

the ability to attribute mental states, beliefs, desires, intents, to oneself and others and to understand that others have different beliefs from self

high level social processing and manipulation - great apes anticipate how others will act according to false beliefs and can take part in deception

machiavellian intelligence

cooperation and competition; ability to navigate complex social groups and manipulate others for personal gain

gelada monkeys suppress copulating vocalizations when a dominant male is near so he doesn’t catch them

tactical deception

when an individual is able to use an normally honest act in a different context to mislead familiar individuals

• low ranking capuchins use alarm calls to disperse groups and obtain food resources

cultural intelligence hypothesis - humans

conitnuation of social intelligence - humans became hypersocial

natural selection selects for ability to learn and invent, but the solutions from that ability are what provide the fitness benefit

opportunities to learn social skills during development facilitate the construction of individual intellectual abilities; infants gravitate towards individuals modeling behavior

assumes:

1. socially learning is more efficient than individual/asocial

2. animals able to learn socially prefer it over individuality

this needs theory of mind and mirror neurons

social cooking hypothesis

expensive brain, cooking allows for food to be more easily digested and release more energy

alloparental care

care by any individual other than the mother (even fathers)

presence of kin is a positive influence on offspring survival

types: provisioning/nursing, carrying, communal nesting, babysitting, protection from predators or conspecificcs

grandmother hyptohesis

infants with grandmothers were foun dto be heavier, healthier, and weaned at a younger age

alloparenting primates vs others

20% of primates with allomothering, 64% with some form of shared care

3% of mammals, 9 % of birds

hypotheses for alloparental care

nepotism - directed towards kin

learning-to-mother - especially when care is provided by young females

buying time - learn skills in the safety of a group until breeding opportunities are available

reciprocal altruism - in exchange for reciprocation of the similar or other service

conditions favorable to alloparenting

mothers think its safe

social species with small groups

altricial offspring with long dependency

collective and extractive foraging

unpredictable climates

• risk of failure is high, alone risk of starvation is high, sharing reduces risk

cooperation in hunter-gatherers

band-wide food sharing, dividion of labor, cooperative fppd acquisition, high levels of allomaternal child care

cooperative breeding —> alloparenting

prosocial and other behavior arose from cooperative breeding

what is culture?

Culture is group-specific behavior that is acquired, at least in part, from social influences

Traditions are ‘behavioral practices that are inherited over generations’

Must eliminate ecological differences alone, and genetic predisposition (so culture can never be proven if only transmitted from mother to child)

6 criteria for animal culture

1. innovation - new pattern of behavior

2. dissemination - transmission of pattern from innovator to another

3. standardization - pattern becoming consistent within and accross performers

4. durability - pattern persists when innovator is absent

5. diffusion - spreads across social units via dispersal

6. tradition - pattern endures across generations

2 hypotheses for innovation - Extra credit

necessity - innovation occurs when resources are limited, often seen in foraging behaviors; individuals who are more desperate are more likely to try things

opportunity - innovation emerges when there are more opportunities for it to exist; higher likelihood of coming across nuts = innovations for how to break them open; immatures are more likely to innovate but they don’t have an audience

how to characterize animal culture

peering, observing, and heightened attention from immature individuals. the longer they observe, the better they become

examples for culture in nhp

termite fishing, potato washing in japanese macaques, hand-clasp grooming, some orangutans use leaves as umbrellas, using sticks to get seeds, capuchin eye-poking

modes of learning

lcoal enhancement - individuals are drawn to an area because others of the same species, but everyone is independently discovering a method

social facilitation - conspecific is not doing the behavior, but just by having someone there an individual is more likely to solve a problem (performing under pressure)

social learning

• emulation: seeing an individual do a task and do the same task in their own way

• imitation - see someone edo a task and copy them (requires mirror neurons so not every species is capable)

teaching - only humans do proactive teaching

horizontal vs vertical transmission

horizontal - between peer groups of same gen

vertical - learning from parents or previous gen - cant rule out genetic predisposition

phase 1: mother

motivation for peering behavior is due to information not resources, because it does not peak at weaning

peering behavior is correlated to food processing complexity or rare food resources

phase 2: outward facind

learning niased towards those with percieved success or knowledge, older/high-ranking models, sex, comformity (copy the majority)

learning at dispersal

immigrant individuals will follow the practices of their new group, even at the expense of efficiency

primate communication components

signal - produced by the actor (expressions, ordors, vocal, multimodal)

motivation - internal state of the actor (fear, aggression, alarm, sexual interest; may not be concious)

meaning - message recieved by recipient; how individuals respond can help ascertain motivation

function - what is the adaptive advantage of the communication? it can be costly to signal (calorically and predation, infanticide); importance can be maintenance of complex social environment, cooperation, learning and sharing of information

modes of communication

tactile, olfactory (strepps), visual, gesture, vocal

factors influencing signals

distance, topography, number of sympatric species living in the same place, costs of predation, energetic costs, body size and anatomy (deeper=larger; honest signals?)

tactile communication

mother-infant, social play, grooming, mating, reassuring hugs to avoid agression and reconcile

olfactory communication

pheremones released from glands, most functionally in female reproductive condition

often passive but can be active: urine washing, scent washing

visual communication

trend in primates for enhanced visual acuity; more important in anthropoids + more facial muscles in anthropoids

coloration can be protective (for infants too) and can be used as conspecific communication; inconsistent relationships with group size

• could be for species recognition to prevent hybridization

• sexual selection - bright faces often correspond to testosterone and dominance rank

gestural communication

historical focus on great apes; intentional and goal-directed towards an individual; must be within view of individual, and signaler is persistant until goal is achieved

flexible - different gestures for same outcome, single gesture for many goals

development (ontogeny) hypothesis

• innate, are gestures produced is absence of signal - supported

• ontogenetic ritualization - signal produced and reinforced by group mates during development

vocal communication

wider audience than gestural; greater distances, but always eavesdropping

within and between species

long-distance calls often for territoriality - male titis duet on border patrols, howler monkeys have special throat sacks

are they learned? they have dialects that change when they join new groups; vervet monkeys have different calls for aerial and terrestrial predators which young ones mix up

unique features of human language

grammar

the ability to put phrases in different orders for different meanings (syntax)

communication vs language

language is specific to humans - semantics, phonetics, grammar, pragmatics, morphology, spoken

teaching human language to nonhuman primates

only can be done with immatures

up to 250 signs used in the right context

but is it imitation or actually understanding, especially when reward driven.

nonhumans have few words with only a few meanings that are mostly instinctive and lack grammar/syntax

humans have many words with infinite meanings that control grammer and syntax for detailed messages, and are learned

primates and disease

primates are especially vulnerable to disease transmission - long birth intervals, long development, single births

primates push off immune function early on to maximize growth and development for survival later on

zoonotic disease

transmission between humans and animals; over 20% of primates have zoonotic parasites

disease as a selective pressure

biologically:

at the time of the transition to more social/promiscuous, there is higher selection for immune function genes

MHC diversity correlates with pathogen/parasite diversity

humans with higher proportions of neanderthal DNA were less likely to get covid

behaviorally:

alter movement patterns to avoid transmission, altering sleeping sites, defecation sites, medicinal plant use, exclusion of individuals with sickness behaviors and high rates of aggression against them

positive relationship between group size and rate of parasitism

super spreaders

high risk groups among many host-parasite systems; 20% of population will spread 80% of the disease. children in humans

fine vs coarse social interactions

fine: individual sociality and behavior (mating, grouping)

coarse: group level (territoriality, dispersal)

dominant individual and disease

higher disease exposure, but those costs can be offset by fitness, access to food

territoriality and disease buffering

quarantine - beneficial for reducing disease

but may promote environmental transmission through increased home range intensity

disease in fragmented landscape

increasing interactions between humans and wildlife - more zoonotic disease

increases in population density and within group disease

increased physiological stress and reduced quality diets

what is the relationship between collectivism in societies and disease prevalence? - 5 extra credit point

cultures and societies that experience more disease outbreaks hstorically are more collectivist over thousands of years

eastern - more collectivism, generally in covernmental structures and rule following

we don’t know why

equator and pathogens

bacteria more present at the equator because of the long warm period. same places as spices, and spices have been used as remidies

extroversion

societal disposition to extroversion enhanced risk of disease. if countires have a long history of outbreaks, they are more introverted. culture has been shaped by historical outbreaks

collectivism enforces ____?

norms - should select for norms because the group follows a pattern

individualists are less confined by norms and thus are more impacted by disease

allele for collectivism

short allele for serotonin - correlated with higher collectivism

what works together to impact health

early life adversity - earlier is worse (sensitive-period hypothesis)

social integration

social status

thrifty-phenotype

slow metabolism to turn food into energy without wasting any, but maladaptive as food becomes available

developmental constraints hypothesis

early life effect adaptations allow immediate survival but are detrimental in the long term

who had the neato

the male baboon

social structure of caltrichids

pair bonded

social structure of colobines and langurs

harem - folivore paradox

human ideal group size

120

group size vs cortex size

positively correlated