491 terms

Human Ev 2

most extant primate species located here
past 30 years
5 new primate species discovered
300% increase in known nocturnal species
Lesula Monkey
DRC Sept 2012, only 2nd discovery in 28 years
Orangutans, Gorillas, Chimps/Bonobos, Humans
more primate diveristy in past or present?
First Primates date
50-60 mya
First Hominins dates
5-7 mya
Furst Homo sapiens
200,000 ya
the most ancient primates, modern day descendents still possess many primitive traits (lemurs, lorises, tarsiers)
diurnal, greater emphasis on vision, relatively large brains (NWM, OWM, Hominoids)
New World Monkeys (round, sideways facing nostrils) Anthropoids
Old World Monkeys and Hominoids (humans, apes) narrow, downward facing nostrils. Anthropoids
General Characteristics of Primates
arboreal, grasping hands/feet, nails instead of claws, forward-facing eyes (binocular vision), post-orbital bar/enclosure, big brains, social animals
Tree-dwelling, very capable of rapid movement through trees
Grasping Hands/Feet
five digits on each hand or foot, prehensile (capable of grasping objects), some prehensile tails
Grasping Reflex
newborn human infants also have strong grasping reflexes
Nails, no claws
Primate hands and feet have expanded tactile pads and nails instead of claws, protect sensitive skin at ends of fingers/toes, enhanced sense of touch
Forward Facing Eyes: Binocular Steroscopic Vision
3D nature of arboreal life requires depth perception to judge distances (overlapping fields of vision, both sides of the brain receiving images from both eyes), reduction in dependence smell; Overlapping fields of vision- fields of vision for each eye overlap, which provides depth perception
Enclosed Eye Sockets
Haplorhine (anthropids and tarsiers)- post orbital closure, fully enclosed eye socket to protect, diurnal so rely on vision
Strepsirhine (all prosimians but Tarsiers)- post-orbital bar, mainly nocturnal primates with decreased reliance on vision
Canine- no bar/bony socket to protect
Relatively Big Brains
larger than expect, more complex, body control and coordination areas, visual abilities, learning, intelligence
advantages- detect/defend against predators, access to food and mates, assist caring of offspring, grooming behaviors- hygienic and form social bonds
Living in groups
Being tolerant, forming relationships
Equipped for Sociality
scent marking/detection, communicative postures/faces, diverse vocal, perceptive to other's reactions/expectations, cue individuals for social interactions
Why study primates
we are primates, evolution, uniqueness, conservation
Who Study
Interdisciplinary pursuit: biologists (growth, evolution, taxonomy etc), Psychologists (cognitive capacities), Anthro (models of behaivor)
Nonhuman primate studies inform about (human ev)
morphology, ecology, sociality, cognition
active during the daylight hours; inactive or sleeping at night
active day or night
active during night; inactive or sleeping during day
Activity Budgets
how primates allocate time to essential activities (rest, Feed, Travel, Other (social)
non-insect vertebrates
non-reproductive parts of plants (leaves, stems, shoots, pith, bark)
Majority of primates (diet classification)
fruigivore-folivore or insectivore-frugivore
ground dwelling
partially ground-dwelling
Forest Floor
ground level
area below trees, but above ground
forest cover
emergent trees
crown above forest canopy
Daily Path Length or Day Range
distance traveled each day
Home Range
area used by a primate
Territorial Primates
defend the entire resource area that they exploit from intrusions
Grouping Categories
One male/multifemale
One female/multimale
One female/one male

Stable Social Group
group composition remains stable
group compostion is fluid, depending on ecological or social factors
single adult male and a single adult female
(Callitricheds, oul monkeys, titi monkeys)
single male and multiple females
(Nocturnal prsimians and orangutans)
single breeding female and multiple males
(Moustached tamarins)
Egyptian Primate Depiction
3000BC, Thoth, god of wisdom, baboons, scribes, measurement, sclaes, moon
Hindu Primate Depiction
500 BCE, Hanuman, aid Lord Rama against evil forces, strength, devotion
Pre Classic Mayan Primate Depiction
divine creatures, sacred, underworld, creation myths
Tulp's Dissection
Western, 1641, surgeon, "The Anatomy Lesson", first to provide scientific info on great ape, (female ape orangutan or chimp?)
Charles Darwin on Baboons
"Origin of man now proved. Metaphysic must flourish. He who understands baboon would do more towards metaphysics than Locke"
minds were biological adaptations with evolutionary histories that can be studied by making systematic comparisons between related species
1890s, go to Gabon, cage in forest to protect himself, observe in wild
Robert Yerkes
1916, article in Science call for establishment of primate research institute for systematic study of fundamental instincts/social relations of primates, reason that primates, bc of evolutionary closeness to humans, could shed most light on the roots of human behavior
(In 1929, The Great Apes, by Robert and Ada Yerkes), also sponsor 2 expeditions to Africa- study/collect apes for lab
Mary Bradley
1920s, and husband travel to Africa w/ big game hunter (Carle Akeley) to collect gorilla specimens for American Museum of Natural History. 1926- Akeley return to study gorillas but die
Clarence Ray Carpenter
1931-1934; observe howler monkeys on Barro Colorado island, spider monkeys in Panama; 1937- go on multidisciplinary expedition to study langurs in Thailand
(Sherwood Washburn was also on this "Asiatic Primate Expedition" as a graduate student)
Cold Spring Harbor Symposia of Quantitative Biology
1950, 129 prominent biologists and anthropologists met to discuss human evolution and other topics, inspire by meeting
Sherwood Washburn
The New Physical Anthropology, American physical anthropologist specializing in primate anatomy, encouraged anthropologists to use new techniques to study human evolution, encouraged young scientists to apply ethnographic methods/theory used by sociocultural anthropologists to study of wild baboons (Baboons are semi-terrestrial and live in open woodland savanna habitats, thought to be similar to those inhabited by our a human ancestors)
Jeanne and Stuart Altmann
1963-1964, study yellow baboons in Amboseli Kenya, foucs on processes at individual/group and pop levels
Japan Primatology
1948- Kinjii Imanishi, Japanese macaques
1958- Japan Monkey Centre Insitute and Museum of Primatology, Imanishi and ITani on anthropoid investigation in africa
Jolly, Sussman
1960s- lemurs
Louis Leakey
British paleontologist, help establish long-term studies of chimpanzees, gorillas, and orangutas
Jane Goodall
1961- chimps
Dian Fossey
1966 mountain gorillas
1971- orangutans (Borneo)
Why study teeth
diet, sexual dimoprhism (social structure), comparison, well-preserved
Dental Formula
Shorthand method of describing the number of each type of tooth in one-half of the jaw in a mammal
Humans- 2:1:2:3 (upper jaw) (3 molars, 2 premolars, 1 canine, 2 incisors)
Same dental formula
Humans and Old World Monkeys
the most ancient primates, modern day descendants still possess many primitive traits
(Lemurs, lorises, tarsiers)
Diurnal, greater emphasis on vision, relatively large brains
(New World Monkeys, Old World Monkeys, Hominoids)
often lack one of the general characteristics of primates-
(Some prosimians have a single claw on each hand or foot
Prosimians rely more on a sense of smell than do anthropoids
Prosimian brains are generally smaller relative to body size than anthropoids
They tend to be small and solitary
Many prosimians are nocturnal)
Madagascar, lemurs, sifakaas, indriids, aye ayes
Lemur Locomotion
vertical clinger/leapers
Smallest Primates eat
insects, gums
Smaller primates eat
Large primates eat
Tarsier diet
all animal prey (insects)
Lemur Social Scene
some multi-male/multi-female, >25% monogamous paris (high), FEMALE DOMINANCE
Aye Aye
(Lemuroidea), only in madagascar, feeds on insects, specialized middle finger, solitary lifestyle, post-orbital bar, 1:0:1:0, 1:0:0:3
lorises, pottos, galagos, slow quadrupedal locomotion (no leap), Africa, Asia, move slowly- avoid detection, insects
(Loridae) bush babies (crying baby), good leapers, longer hindlimbs than forelimbs
Nocturnal Prosimians
aye aye, bushbaby, greater bamboo lemur
Loris, Potto, and Galago Social Scene
Solitary or small groups, All prosimians (except tarsiers) have reflective tapetum, which is a layer in the retina that reflects light and enhances night vision
Prosimian Diet
large animal prey component, also comsume some fruit
Toilet/Grooming Claw
Strepsirhine Trait, Characteristic of all prosimians, it's a specialized claw or nail on the foot used for personal grooming
Tooth Comb
Strepsirhine Trait, dental structure of strepsirhines used in grooming, comprised of lower incisors and canine
Strepsirhine Dental Formula
Lemurs, Sifakas, INdriids, Lorises, Galagos
Philippines, Indonesia, small (4-5 oz), hunt at night for insects, rotate head
pairs or small social groups, park infants (dont carry- limit social learning opportunities)
Stresirhines and Haplorhines
alternative to the traditional classification of prosimians and anthropoids
(Tarsiers don't fit into traditional classification, bc have many anthropoid characteristics)
Easy Distinction:
Strepsirhines- primates w/ wet noses
Haplorhines- primates w/o wet noses
Tarsier Traits Resembling Anthropoids
no reflective tapetum (strepsirhines have), no wet noses, post-orbital closure like antrhopoids, monthly sexual swellings of females like anthropoids
New World Primate Origins
"Floating Island"model of africa
Callitrichids (tamarins, marmosets)
Cebids (squirrel monkeys, capuchins, owl monkey)
Pithecids (saki monkeys, uakaris)
Atelids (spider/holwer/woolly monkeys)
Unique dental formula 2:1:3:2 (only 2 molars)
Nail on hallux, claws on all other digits
10-12 species of tamarins, 14 marmosets
Central America and Amaoznia
Body size: approx 110-500 grams
Claws on all digits except big toe
Diet: fruit and invertebrates, nectar
Group Structure
Single breeding female dominant over other group members
Births: twins, as often as every 6 months
Males help carry infants
New World Monkey Dental Form
Cebids: Owl Monkeys
9 species
South and Central American (Panama to Argentina)
Only nocturnal anthropoid primate
Body size: approx 1 kg
Diet: fruit, leaves, insects
Births: 1 offspring per year
Monogamous pairs
Male helps care for infants
Cebids: Squirrel Monkeys
2 species (Saimiri oerstedii and Saimiri sciureus)
Central and South America
Body size: approx 800 g
Diet: frugivorous and insectivorous
Sharp crests on molars
Birth: Single births every year, breeding highly seasonal
Group sizes: Large (20-50 individuals)
Cebids: Capuchins
4 species of genus Cebus
Central and South America
Body size: sexually dimorphic
Males: 3.5 kg
Females: 2.5 kg
Prehensile tail
Diet: fruit and animal matter
Tool use (cracking nuts and opening clams) video
Relatively large brain size, slow life histories
Group size: 8-30 individuals
Pithecids: Pithecia, Chiropotes, Cacajoa
3 genera (Pithecio (saki monkeys), Chiropotes (bearded saki),Cacajoa (Uakaris)
Guianas, Suriname and Northeastern Brazil
Swamps, hard to study
Body size: 2-3 kg
Dental specializations for hard foods (fruits and seeds)
Large, procumbent incisors and large canines
Range of social organization
Some monogamous groups, some more fission-fusion (larger groups, break apart during different times of the day to forage)
Atelids: Spider Monkeys
4 species of the genus Ateles
Yucatan peninsula throughout Amazonia
Habitat: primary rainforests, upper canopy
Body size: 7-9 kg
Prehensile tail, Brachiation
Fission-fusion social organization
Large groups that split up during day
Diet: primarily fruit
Atelids: Muriquis
Genus Brachyteles (wooly spider monkey or muriqui)
Isolated patches in Brazilian Atlantic coast
Highly endangered
Largest New World Primate (8-10 kg)
Prehensile tail
Slow life histories
Females do not reach maturation until ~9 years of age
Diet: frugivorous/folivorous
Atelids: Howler Monkeys
Many species of the genus Alouatta
southern Mexico to Argentina
many different habitats (Dry deciduous forests, cloudforests, degraded forests)
Sexually dimorphic (4-8 kg)
Color (Females- golden color Males- black)
Hyoid Bone (Males- large)
Prehensile tails
More rapid life stories
Females reach maturation at 3.5 years
Most folivorous NWP (Approx 50% leaves)
Small day ranges, sedentary lifestyle (Tactic for low energy diet?)
Living Lab Methods
Behavioral Data
follow around, write down everything, toughness data
Toughness Data
no significant differences btwn juvenile and adult diets (few food choices) but juveniles- less time eating tough foods, they struggle with transition to adul diet (fall back to mother's milk during dry season, as resource toughness increases), mortality during dry increase
Where find OWM
Africa, Asia
Old World Monkeys Cercopithecoids (Cercopithecinea and Colobinae)
Baboons, macaques, mangabeys, langurs, dirunal, generally larger than NWM, partly terrestrial, NOT prehensile tails, ischial callosities
Ischial Callosities
calluses on rump of OWM, sleep sitting upright or on thin branches/cliffs beyond reach of predators
OWM Diet
Cheek Pouches
saces in lower cheek, store food, consume food later or at safe distance
Old World Monkeys Subfamily: Colobinae
colobus monkeys, langurs, more leaves and seeds than cercopithecinae,no cheek pouches, specialized stomaches, high-cusp molars
Sacculated Stomach
chambered stomach helps break down plant material
Dental Adaptations: Feeding on Leaves
BILOPHODONT molars with shearing crests
slice up leaves
Cercopithecoidea Dental Formula
Cercopithecoidea Sexual Dimorphism
difference in body size (m/f)
Baboons Sexual Dimorphism
show it
Cercopithecoidea Politics Within and Between the Sexes
Group living: dominant male with multiple females
primate politics: domiance hierarchies, alliances
living in the same group as one' matrilineal kin, Females remain in their natal group, and males transfer
Many baboons, macaques
Negotiating Relationships with Other Females
disperse, stays, have social skills to integrate
Benefits of Social Skills
Benefits of female's social skills-
Achieving higher rank
Support from group members
Increased access to resources necessary for reproduction
More offspring survive to age of reproduction
Limiting Resources and Competition
female- food resource availability
males- mating opportunities
Egalitarian Relationships
equality of all individuals; especially in political, economic, or social life
can be challenges to the hierarchical structure
dominance interactions: BI-DIRECTIONAL
patronage bestowed or favoritism shown on basis of family relationships, as in business and politics
Challenges to the hierarchical structure are rare
dominance interactions: UNI-DIRECTIONAL
Baboon Social System
Multi-male, multi-female group
Group size varies from 17-77
Females remain in their natal groups for their entire lives
Males emigrate into a new social group to breed when they reach adult size
Baboon Dominance Among Females
assert their rank over submissive females by-Threats, mild aggression, biting, chasing, displacing at feeding sites, fighting
Submissive animals respond by- Averting their head/body, avoiding the dominant animal, crouching, screaming
Baboon Stability of Female Rank
young inherit mother rank, stable for long periods, high ranking matriline (offspring- high status), low ranking (low)
Baboon Reproductive Fitness of High-Ranking Female Daughters
reach sexual maturity younger, reproduce earlier, increased overall potential fitness
Baboon Female Coalitions
kinship, relative dominance rank (high support high), mothers/siblings support
Baboon Female Bonding
enhance survival, infants live longer
Female bonding in humans
strengh/quality>number, reduced mortality, better physical/mental health
Baboon Dominance among Males
largest, fighters, not kin, usually youngest immigrants, higher levels of reprodctive success
Baboon Male Coalitions and Fighting Ability
support during fights, not based on kinship, based on fighting ability
Baboon Stability of Male Ranks
~2 years, transfer groups
Baboon Consortships
lag behind, consortship may last a morning, an afternoon, or an entire day
However, a female can have multiple mates during a single estrus period
Female Choice Among Baboons
female choice
Baboon "Friendships"
formed by grooming, maintaining close proximity, infant handling
dexual dimoprhism (weight), multi-male, multi-female, matrilocal, kin bonded, vary in degree of nepotism
Complexity of Social Relationships: Third Party Interventions
Dominant individual- observe individuals forming alliance, break it up such separating interventions in chimps, gelada baboons, and Japanese macaques
Consolation, third-party mediation can facilitate reconciliation after a fight
In contrast, reconciliation occurs among individuals involved in a conflict
Reparing Relationships
Despotic Rhesus Macaques (uni-directionality) don't need repair relationships ~7% post-conflict repair
Egalitarian bonnet macaques (bi-dir) reversals- need repair ~29%
Hominoid Characteristics
large bodied
big/complex brains
Y-5 cusp pattern on molars
suspensory climbers
no tail
orangutans, gorillas, chimps, bonobos, humans
Y-Cusp Pattern on Molars
distinguish from OWM (only 4 in bilophodont pattern)
Suspensory Climbers
Anatomical adaptations for climbing
Broad torso
Long arms
Short legs
Gibbons (Hominoidea)
"lesser apes" (smaller)
long forearms, mobile shoulder, short thumbs, elongated fingers (hook) brachiation
sexually monomorphic
pair bonded, variation
not necessarily monomogous
fruits, seeds, leaves
Extra Pair Copulation
(gibbons) no monogamous
Modes of Primate Communication
Touch, Visual signals (facial expression, postures), Odors, Vocalizations, different detection distance, can be used singly or in combination
Gibbon Communication
defend territories, duet/song, loud
Boreno, "man of forest" Sumatra
sexual dimorphism (canine, sagittal crest, 2x body size)
secondary sexual characteristics (cheek flanges- projet long distance vocal, summon females, territory)
female mate preference
Unflanged Males
sexually mature, but smaller, without cheek pads and largynal sac
flanged males
large cheek pads, large largynal sac, father more offspring
Long Call (Orangutan)
long series of reverberating grunts emitted by flanged males, cheek pads/throat sac/ large body size aid in projection
unflanged male roams in search of females (more mobile)
Orangutan Locomotion
agile climbers, hangers
QUADRUMANOUS (all 4 feet adapted to function as hants)
Orangutan Diet
vary, leaves, MAST FRUITING (every 2-10 years, up to 88% of tree species fruit at 1x) may consume up to 10,000 kcal/day
Orangutan Social Scene
solitary (due to fluctuating resources that don't support large group)
only mate
mother and infant
offspring dependent on mother for longer than any other primate, learn survival skills (~7 year IBI)
dian fossey, 1971, largest primates (males reaching 400 lbs)
Sexual Dimorphism (sagittal crest, canines, size, silverback- fully mature adult males)
Gorilla Locomotion
KNUCKLE WALKING form of mvmt all 4 limbs touch ground, weight of arms rest on knuckles of hand
Gorilla Diet
Eastern (Mountain)= frolivorous, LITTLE FRUIT, mostly leaves
Western (Lowland) more frugivorous
when have the opportunity- prefer fruits
Gorilla Breeding Group
1 male, mulitple females ("harem groups")
silverback with many females/offspring
Gorilla Social Scene
BREEDING GROUP (at least 1 male and 1 breeding female, 7-8 individuals)
SOLITARY MALE (single silverback) 20-41% of groups
BACHELOR GROUP (silverback and immature males, very rare)
Female Gorilla Dispersal
disperse from natal group (avoid inbreeding)
Male Gorilla Dispersal
disperse before reaching full adulthood (10-15 yrs)
dispersing males may be solitary, form breeding group, join bachelor gorup
to be reproductively successful MUST ATTRACT FEMALES
Gorilla Male Quality
indicated by crest/body size, coloration, etc.
Gorilla Dominance
silverback dominant to all, mitigates conflicts bwtn females, don't expect rigid dominance hierarchies bc females not related so not much direct contest/comp
Gorilla Infanticide
new silverback kill resident infants (progeny of previous male, females return to sexual reproductivity)
Silverback as Male Protector
care of offspring, play/grooming
Jane Goodall
1961, chimps, no formal academic training/preconceived notions (unbiased), named chimps, describe personalities, conservation
Common Chimps
Pan troglodytes
Where find chimps
equatorial Africa (4 different subspecies)
Chimp Sexual Dimorphism
only slight, male canine more defined, not as defined sagital crest as gorillas
Chimp Locomotion
climbing, hanging, knuckle walking, adpet in both terrestrial and arboreal
Chimp Diet
frugivorous, one of most diverse diets of primates, but constrained by enviro (arid- eat 45 plant food types; woodland- 328 types)
Chimp Tool Use
use of a detached object to achieve a goal, aside from humans, chimps are the most skilled tool users in the animal kingdom
Tool sets, modification for different tasks
Chimp Habitats
range from savannas (low tree density, sparse canopy coverage, hot, more predation pressure) to dense tropical forests (higher tree diversity, more canopy coverage, higher rainfal-productivity)
Chimp Behavorial Adaptations to Hot
more terrestrial, increased resting, cave use, well-digging, pool parties (video)
Chimp Self Recognition
awareness of one's own mental states, pass mark test (concept of bodily self)
Chimp Society
most diurnal primates live in stable gorups (maintain group cohesion to cope with enviro/social influences) contrast with fissuion-fusion social systems (group memebrs reside within same home range, maintain closer relations with each other than conspecifics in other groups BUT separate into smaller gorups on reg basis)
Fissuion-Fusion Social Systems
group memebrs reside within same home range, maintain closer relations with each other than conspecifics in other groups BUT separate into smaller gorups on reg basis
Group-based Fission-Fusion
temproary subgrouping consist of more FORMALIZED AND STABLE GROUPS
subgroupings PREDICTABLE
Individual-based Fission-Fusion
temp subgroupings of VARYING SIZE AND COMPOSTION which may change in day
NOT PREDICTABLE, requires knowledge of all relationships within group
Chimp Party Sizes
4-10, influenced by group demographics, resource availability, presence of sexually receptive females
living in the same group as one's patrilineal kin
Male chimps and bonobos reside in their natal group throughout their lives
Promotes strong male bonds
Female chimps and bonobos disperse from their natal group (Maintain gene flow)
Chimpanzee Male Bonding
Establishing affiliations often involves-
Proximity and association
Grooming (social component too)
Social support
Kinship is not always good at predicting affiliative relationships
Results of Male Cooperation
secure positions in social hierarchy, hunt, guard mates from other mates, border patrols to defend territory
Linear Dominance Hierarchy
each individual dominates all individuals below him and not above him
(fission-fusion makes it hard for high-ranking individuals to dominate) political maneuvering may have to take place btwn males in another subgroup
Dominance Hierarchy
alpha male
beta male
middle rank
low rank
Alpha Male Lifestyle
displays more often (maintain status), more mating opportunities, more aggression
Contexts of Chimpanzee Aggression
Males (reunion, sexual comp)
females (plant-food competition, protection)
Sexual Swellings
Approx 10% of OWM/apes have sexual signals about ovulation
multi-male, multi-female
breed year-round
FLAT: During Menstrual phase
INFLATED: rising levels of progesterone and estrogen before ovulation
MAX TUMESCENT: 2—3 days near the day of ovulation (male aggression highest)
Inflation of sex skin can increase female body weight by 14% in baboons; 25% in red colobus
males judge when fighting for females should have highest payoff
social passport for dispersing female chimps
Male competition may be relaxed when-
Females are NOT monopolizeable, when there are many females in estrous
FEMALE CHOICE overrides male strategies, when females dominate males
Promiscuous Apes
polygamous (bonobos and chimps)
both sexes mate with multiple partners
lots of copulations per birth
Chimp Hunting
energetic benefits
Male Chimps' Softer Side
altruism towards unrelated group members (the case of adoption)
(pygmy chimps) more southern compared to chimps, some sexual dimorphism, canines, no sagital crest, frugivorous, diet similar to chimps but MORE LEAVES AND HERBS (little less fruit) ecological explanations for differences
Differentiating Bonobos and Chimps
Bonobos- pink lips, dark-faced infants, middle part, lighter build, longer arms and legs than common chimps, walk bipedally more often than chimps
chimps- dark lips, light faced infants
Bonobo Social Scene
fission-fusion, males stay in natal groups, females transfer, female dominance (priority access to preferred foods, dominant mothers promote son's dominance rank)
Bonobo Social Associations
female bonobos more social than female chimps, higher degree of socializing BTWN SEXES
Genital-Genital Rubbing
embrace each other ventro-ventrally and rub their genital swellings against each other
Bonobo Benefit of Sexual Behavior
Development of affiliative relationships
Facilitation of reconciliation after conflict
Tension regulation
H-G %
Humans have lived in a hunter-gatherer environment for 95% of our existence
Humans' Physiological Characteristics, Cognitive Abilities, Unique Behaviors
large, complex brains
extended period of juvenile dependence
long post-reproductive life
prosocial emotions that promote extreme cooperation
complex communication system
extensive reliance on social learning
cumulative culture
Environment of Evolutionary Adaptedness
social, technological and ecological conditions under which human mental abilities evolved
Who are H-G People
forage on wild foods, no cultivation or animal husbandry, documented 478 h-g societies, derive less than 10% diet from domesticated foods
Humans are Tropical Primates
originally evolved in tropical enviro
BIOLOGICAL ADAPTATIONS (aided in new enviros- cold weather/high altitude)
CULTURAL ADAPTATIONS (allow us to range beyond biological limiations)
facilitate pop growth
Human Pop Density
humans=most widely distributed living primate species
Human Sexual Dimorphism
little body size dimorph
almost no canine dimorph
Human Locomotion
Bipedalism= moving on 2 legs
adaptations to bipedalism (big toe aligned with other toes, long day ranges)
Central Place Foraging
describes behavior of a forager that must retun to a particular place to consume food/share food with mate/offspring
essential to human life
Residential Mobility
move location, access new resources
Human Social Scene
vary, bio needs limit (food, reproduction, care for kids)
Human Diet (H-G)
(bonobos, chimps, gorillas, orang- very little meat, fruit/leaves!)
humans, universal in human society
Cooerpative Foraging
sexual division of labor with men hunting and women gathering
divisions not exclusive
Sharing and Provisioning
humans, food production exceeds food consumption, food shared with kids/others
Human Social Scene
varies, typically egalitarian with male-female pair bonds
Human Reproduction
preferene for polygyny (single male, mult females) but more common for man to have single wife
h-g often polygamous over lifetime
Human Dispersal
Either sex may disperse or remain in natal group
adult bros/sis often co-reside (transfer to same group)
most individuals in residential group- unrelated adults
EXCEL IN SOCIAL LEARNING AND CUMULATIVE CULTURE (disperse individuals carry skills to new groups)
Human Fusion-Fission Society
among foragers- 3 levels
1. ethno-linguistic group (tribe) which may never asemble in one place
2. residential or local group (camp/band)
3. daily foraging party
Complex Dynamics of Fission-Fusion Society
fluid social dynamics-
every day- group splits to smaller (forage)
foraging parties may also fission/fuse during day
one camp (local group) may fuse/fission with other camps
individuals also move back/forth btwn camps
no crops/lifestock/permanent shelters
1000, Tanzania, Central Rift Valley, Serengeti Plateau (bountiful, dangers)
Harvard, study Hadza, began 1995, parental care, mate preferences, mating systems, cooperation,etc. gone 15x, 4 year equivalent
Hadza Camp
loose affiliations, relatives, in-laws, friends
no official leaders
individual autonomy (NO AUTHORITY, NO MORE WEALTH)
women gather berries, fruit, tubers
Collect honey and hunt
hunt with poison arrows (zebras, buffalo, baboon) don't hunt elephants but will scavenge carcass
rather than drag big game back, sometimes camp will move to it
Hadza Childhood
Young children carried by mother
Toddlers stay in camp with grandparent group members
Older children may assist with some gathering
Hadza Workday
4-6 hours/day pursuing food
Residing in a Changing Social Landscape
The extent of Hadza land has been greatly reduced by agriculture and encroachment
h-g, w.ern congo basin, the 'pygmy' (small stature- adaptation to enviro- nutrition, metabolic, thermoreg) people of central africa, rainforests, selfID "forest ppls"
Ba'Aka Dietary Diversity
63 plant species, 20 insect species, honey from 8 bees, 28 animal prey, also trade w/ farmer neighbors for agriculture goods
Ba'Aka Shifting Camps
Communities shift location to set up temporary camps to follow food resources
Hunting with nets, honey gathering, and collecting caterpillars
Paternal Care Among Ba'aka
Hewlett tested the hypothesis that infants attached to fathers thru "rough and tumble" play interactions Infants attached to mothers thru regular, sensitive care Studies in urban setting showed that vigorous play was distinctive feature of fathers' style of interaction w/ infants
Ba'Aka fathers
men holding/within arms reach of infant 47% if day (holding 22%), more likely to show affection while holding than mothers, contrast to some h-g fathers (2.6% hold)
Cooperative Net Hunts
Aka men more likely to be around kids bc entire family participates in cooperative net hunts Mothers and fathers spent most of the day together, extensively communicated to effectively trap animals, create environment that promotes male care of infants
Ba'aka Society and Ceremony
egalitarian, fission-fusion, complex interaction with their forest enviro (JENGI- spirit of the forest, one of the few words common to many of the diverse languages spoken by forest peoples)
behavior that is shared, learned and socially transmitted
Culture mediates human experience
Primate Brains
larger than expected for body size
more complex than most animals
larger areas associated with body control and coordination
lareger areas associated with visual abilities, learning and intelligence
increased convolution (folding of brain tissue) of cerebral cortex
Human Brain
skulls rounded to accomodate large brain, faces smaller/flatter than other organisms
absolute brain size
NOT USEFUL MEASURE have to consider relationship btwn brain size and body size
The study of the change in proportion of various body parts as a consequence of different growth rates
how traits change with body size
brian size and body size relationship fairly predictable EXCEPT HUMANS (3x what expected)
Encephalization Quotient
more refined measurement than the brain to body size mass ratio bc it takes into account allometric effects
EQ= observed brain volume / prediceted brain volume
humans 5.1-7.4 chimp 2.2
brain comprised of 100 biollion processing cells
neurons similar to number of trees in amazon, number of synapses= number of leaves
neurons communicate with each other by making connections, estimated 60 trillion connections in human brain
human brain
directs conscious or volitional motor functions of body, senses
motion, balance, learning
automatic actions, breathing digestion
Cerebral Cortex
"bark" sheet of neural tissue that is outermost to the cerebrum of the mammalian brain, includes the cerebrum and cerebellum
critical role in memor, attention, percpetual, awareness, thought, language, consciousness
Brain Anatomy
front- planning, memory inhibition
top- motor and sensation
back- vision
bottom- hearing and advanced visual processing
Gray Matter
color is gray, contains the cell bodies of the neurons, the cerebral cortex is made of gray matter
White Matter
fibers that connect the neurons into information processing networks, axons are covered with myelin (which is white colored)
increased convolution of cerebral cortex, folding of brain tissue
brain of a human child with the same volume as a chimp youngsters has more cerebral cortex
Brain Cell Development
Nearly 1/2 of brain cells developed during the first 1/2 of pregnancy, infant 2x cells and connections as adult, Development requires pruning back of overproduction
Brain Development continues after birth, through adolescence, Most synapses- 1 yr
Energetically Expensive
Consumes more energy
Brains of dogs and cats use 4-6% of their body metabolism
OWM brain uses 9% of their body metabolism, human- 20% of metabolism!
Expanstion of Prefrontal Cortex
implicated in planning complex cognitive behaviors, personality expression and decision making
Social Brain Hypothesis
why brain so big
brain size most closely correlated w/ size of a species' social group
Keeping track of who is doing what to whom- considerable processing power (bigger groups, need bigger brains)
studies- correlations btwn size of social networks and of specific areas of brain liked to sociality 1 study found a positive relationship between gray matter and number of Facebook friends
Plastic Brains
london taxi driver, greater volume of gray matter posterior hippocampus, 'the knowledge'
Behavioral Reflections of Brain
Greater size and complexity of the primate brain is reflected in behaviors- Social Cognition and Learning
Strong relationship btwn reproduction, care of offspring, and learning
Primates spend longer time growing up, (biologically and socially)
Primate children have a lot to learn about their environment and society
Social Learning
an individual learns a new behavior or strategy by observing and attempting to reproduce conspecific's behavior
learned behaviors, koshima- macaques given yams, imo wash, spread to group, spearating wheat form sand
more efficient than tiral and error
The Benefits of Social Learning
may increase their reproductive success
Take advantage of things learned by other members of the group
Pass on skills to their offspring that would otherwise be difficult to acquire
Exploit past experiences elders in key circumstances (such as droughts)
Process of organic evolution may be supplemented by cultural evolution
Local Enhancement
transmission of behavior by attention being drawn to a particular LOCALE IN THE ENVIRO chimps drawn to tool use sites
Stimulus Enhancement
transmissions of behavior by attention being DRAWN TO AN OBJECT or part of an object, irrespective of its location
monkey poke stick for termites
learning from SEEING END RESULT, not how to accomplish the task
same ENDS not means
Learning from SEEING IT BE DONE, learning about the form of the act
quick way of acquiring complex skill, avoid costly errors
amazing brain feat
a penetrating and often sudden understanding of a complex situation or problem
More technical definitions of insight-
Capacity for understanding one's own or another's mental processes
Immediate understanding of the significance of an event or action
Broca's Area
Language Production, Grammar, Syntax
Wernicke's Area
Language Perception and Comprehension
amazing brain feat
humans- exceptional short/long term capabilities
3 basic processes-
encoding (storing info)
maintenance (keeping it "alive")
retrieval (finding encoded info)
apes advanced memory?
research at Primate Research institute in Japan- excellent short term memory (vid)
Planning and Abstraction
amazing feat of brain
Important Study Diet
"the single most important parameter underlying behavioral and ecological differences among living primates"
Many of chronic degenerative diseases facing society may be result of discordance btwn what we eat today and what we evolved to eat
Nutritional Adaptation
proper nutrition- maintain body, growth, energy needs
too little energy- reduce size/speed of maturation; too much- fat, acceleration of malnutrition
poor nutrition
too much/little food (quality or quantity)
Protein-Calorie Malnutrition
group of nutritional diseases resulting from inadequate amounts of proteins and/or calories
increase in height and weight as their societies modernize
abnormal or excessive fat accumulation that may impair health
Body Mass Index
weight / height^2
>25 overweight; >30 obese
What Causes Obesity?
energy imbalance btwn calories consumed and calories expended
globally- decrease in phys act (sedentary nature of work, tranportation, urbanization) increase energy-dense foods, high in fat/salt/sugars and low in vitamins/nutrients
Total Daily Energy Expenditure
overall physical activity level was greater among Hadza foragers than among Westerners
But control for body size, avg daily energy expenditure of Hadza foragers wasn't statistically different from Westerners
Similarity in Energy Expenditure
similarity in metabolic rates across a broad range of cultures challenges current models suggest obesity is due to decreased energy expenditure
if it is not energy expenditure, then it is ENERGY INTAKE
Body Fat and Activity Level
Relationship btwn % body fat and activity level- apparent (Western pops the least active, have highest body fat; H-g most active, have least body fat)
Ev. of Total Energy Expenditure
evolved trait shaped by nat sel.
responds over evolutionary time to ecological pressures (food availability, predation risk) Humans known to have greater energy expenditure than orangutans, but lower energy expenditure compared to some other mammals
energy, fuel
energy needs vary by sex, height, weight, activity levels, decline with age
Protein needs higher in men than women
(46, 56g)
provide amino acids, deficencies- growth retardation, illness, death
animal products mean eggs fish milk
Changing Diet
general primate adaptation to a diet comprised of large amounts of fruit and vegetation
Primary means of acquiring food thru most of human evolution has been hunting and gathering (h-g begin 2 mya, only 12,000 ya rely on agriculture)
H-G Diet
More than half of energy needs are obtained, not primarily dependent on gathering
compared to W.ern- more protein, less carb, high fat
Humans eat
Bonobo/Chimp/Gor/Orang eat
little meat (including insects)
Hunting and Fishing
Foods differ predictably in their:
distribution and availability in enviro, energy density (kcal/gram), digestibility
Food Source: Leaves/Structural Parts
widespread, easy to find
low energy density
difficult to digest
Food Source: Seeds
relatively scarce
high energy density
hard to digest
Food Source: Fruits
high energy density
relatively scarce, seasonal
easy to digest
this resource may be often defended (territories of chimps/gibbons)
Food Source: Gum
High energy
hard to extract
small meal size
marmoset gauging tree to extract gum
Food Source: Meat (including insects)
hardest to locate in enviro
most energy dense
easiest to digest
McDonald's Meal
easy to locate in enviro
energy and fat dense
Chimp Hunting
hunting in groups, associated with ENERGY BENEFITS (Tai- meat intake INCREASES with # of hunters; Gombe- meat DECREASES with party size, no energy benefit; Ngogo- NOT RELATED
Why hunt in groups? name 3 hypotheses
Male-Bonding Hyp
Meat for Sex Hyp
Meat for Scrap Hyp
Male-Bonding Hypothesis
meat sharing is important for maintenance of cooperative social relationships among males
Meat for Sex
males increase their mating success by sharing meat with estrous females
Meat-scrap Hypothesis
consumption of small quantities of meat may reduce need for particular micronutrients
Leader is exceptional hunter
Frodo (alpha male chimp Gombe Tanzania, initiate hunts, 5 years kill 10% red colobus pop, cog sophistacted)
Humans quality diet
higher than expected for body size
Primate Diet and Digestive System
In relation to our diet quality, humans have a relatively small gut
Energy Minimizers
substantial proportion of time resting, and little time to travel
Feed on leaves which are easy to find, but low in energy
Foliage diet requires long digestion time
Energy Maximizers
rest less, devote more time and energy to foraging and traveling
Foods are more dispersed but higher in energy and easier to digest
Optimal Foraging Theory
suggests that organisms forage in such a way as to maximize their net energy intake per unit time
Capture and consume food containing the most calories while expending the least amount of time possible in doing so
Food Quality and Distribution
FRUIT (rare but more kcal)
LEAVES (abundant/common fewer kcal)
MEAT/BUGS (rare, small, highest energy density)
Diet and Territoriality
fruit specialists- more territorial
howlers, chimps, gibbons, colobus
Morphological Indicate Diet Choice
Teeth and jaws, gut
Colobus monkeys have sacculated stomach for digesting largely leaf-based diet
Reptile Teeth
HOMODONTY all the same, replace thruout life, hold and kill prey, food often eaten whole
Mammalian Teeth
Incisors: chisel, cut, slice, gnaw
Canine: behind incisors, puncture, defense
Premolar: type of back teeth, crush/grind
Molar: furtherst back, crush/grind
(back/cheek teeth)
Advantages of Mammalian Teeth
consume a wide variety of foods
Chewing- increased eating efficiency
Break down pieces of food that can be more easily digested
Saliva- in mouth begins digestive process
Cost of Mammalian Teeth
wear out over time, old- can't eat, serious dental probs, before mod dental hygiene- dental probs serious health threat
Dental Adaptations: LEAVES
Small incisors
Bilophodont molars with shearing crests
Colobus monkeys have bilophodont molars for effectively slicing up leaves
Dental Adaptations: FRUITS
big, broad incisors
low, rounded molars
Chimps have big flat incisors and low rounded molars for eating fruit
Dental Adaptations: GUMS
strong incisors
marmosets have strong incisors to chew thru bark and extract sap
Dental Adaptations: INSECTS
high, sharp cusps on molars
tarsiers have sharp, high-cusped molars to crush up insect exoskeletons
Austraolopithecus afarensis teeth
smaller canines and incisors than chimps
relatively big molars
thick enamel on teeth
likely consumed fruits, hard objects (nuts/seeds), and tubers
Waltern Voegtlin
gastroenterologist, suggestd that following diet similar to that of Paleolithic era- improve health
Paleodiet, Stone Age Diet, or H-G Diet is a nutritional plan based on the presumed diet of ancient hominins
not the solution (little knowledge of their actual diet)
why focus on skeleton?
For locomotion- provide info about both phylogeny and adaptation; Are the best documented aspects of primate locomotor anatomy; Are most useful in reconstructing locomotor habits of fossils
Primate Hands
grasping ability (varies with degree of thumb opposability)
bones of fingers
intermediate part of hand skeleton
bones of wrist
Primate Locomotion
arboreal radiation. but vary
5 Categories of Primate Locomotion
arboreal quadrupedalism
terrestiral quadrupedalism
vertical clinging and leaping
why do primates have diverse locomotor abilities-
SIZE (within same habitat, different sized priamtes face different probs)
ACCESS TO DIFF PARTS FOREST HABITAT (live in open habitats- adapt to terrestrial walking, feed in understory- leapers, high in canopy- quadrupeds and suspensory primates
most common locomotor pattern among primates
Arboreal Quadrupedalism
fast and agile (colobus, marmosets, mangabeys)
slow and cautious (potto, loris)
bodies must be able to provide propulsion on unstable, uneven supports that are small rel to bod size
forelimbs- major role in support/propulsion (distinct shoulder joint, laterally placed- scapula)
long tail (balance)
forelimbs/hindlimbs short, similar length (bring center of gravity closer to arboreal support)
grasping feet (firm base for propulsion, guard against falling)
Terrestrial Quadrupedalism
baboons, patas monkeys, some macaques
relatively rare, NONE show adaptations of terrestrial runners (cheetahs, antelopes)
most of adaptations related to used of more extended limb postures on flat, broad surface. deep trunk, long limbs for striding/speed
restricted shoulder joint (more limited anterior-posterior mvmnt than complex rotational mvmnt)
forelimbs/hindlimbs similar length (effective adaptations for speed and for-aft mvmnt) short toes (suitable for weight bearing, rather than grasping branches) reduced tail (no need for support)
Vertical Clinging/Leaping
Sifaka, bushbaby, tarsier
leaping adaptations have evolved independently in primate groups
long hands (grasping)
long hindlimbs (enable longer leap bc most of propulsive force comes from rapid extension of hindlimbs)
slower, more careful (orangutans, spider monkeys, chimps)
fast "ricochetal" (gibbons)
skeletons show features that enhance ability to reach supports in many directions (long, curved fingers- grasp, mobile wrist joint, very long forelimbs, long hindlimbs, dorally placed scapula- enables reach in all directions)
moving about on 2 legs
HUMANS- stride
Mechanical Probs faced by biped
balance, particularly side to side
difficulty of supporting all body's weight on 2 limbs
Adaptations to Bipedalism
major bony features associated with it found in trunk/lower extremity
short broad pelvis (lowers center of grav, better balance/stability)
cuved lower back (center of mass of trunk forward, closer to hip joint)
large toe aligned with other digits
FORAMEN MAGNUM position= (opening at base of cranium- medulla oblongata) forward
"S" SHAPED SPINE= dorsal/ventral convexity, curvature moves to the center of mass of trunk forward to hip joint
PELVIS= shorter/wider, stability, attachment site for muscles of lower limbs, protects internal organs, bowl shaped!!!!
HIP MUSCLE gluteus medius= shifted positions, allows pelvis to remain stable while 1 leg is lifted during walking
CARRYING ANGLE OF KNEE= width of bodies at knees- less than hips- upper leg bones (femurs) slope inward form hips; humans are knock-kneed, on 1 leg- weight transferred directly beneath bodies- continue to be balanced while 1 leg is swinging
ANKLE JOINT= perpendicular orientation of distal joint surface minimizes potentially damaging shear stress on cartilage (gorillas- angled joint)
BIG TOE aligned with other toes= human foot transformed from grasping appendage to rigid lever for proulsion (push off not grasp)
RIGID FOOT ARCH= spring-like shock absorbers, direct weight thru outside of foot, footprint
LONG LEGS= 75.3 intermembral index, legs longer than arms
Intermembral Index
measure of relative length of the forelimbs and hindlimbs of an animal
humerus + radius / femur + tibia x100
(75.3 for humans- legs longer than arms)
(108 for chimps- arms longer than legs)
longer legs than arms, legs used to propel themselves
study of how anatomical form related to function, also referred to as fucntional morphology
Continuous Contact Brachiation
exchanging handholds
Richoteal Braciation
achieving momentum that propels the body thru the air to a "flight" period when the gibbon has no contact with supports
bipedalism in fossil record, trail of hominid footprints fossilized in volcanic ash, Mary Leakey's expedition at Laetoli Tanzania 1978, 3.6 mya
Primate Locomotor Habits
IMP primates habitually use many types of locomotion, many arboreal quadrupeds leap, some leapers are also suspensory, terrestrial quadrupeds may also walk bipedally
Advantages of Bipedlism
human foragers- long day ranges
hands free for other activities
more efficient (costs less energy)
conserve energy while foraging
Chimp v Human Bipedalism
chimps- crouched; use lots of muscle (hip)- more energy used
Disadvantage of Bipedalism + Big Brain
risks associated with the combination of bipedalism and encephalization
Demands of bipedal locomotion have restricted size of pelvis and birth canal
Humans unique among large-bodied primates in producing infants w/ large heads relative to mother's weight and birth canal dimensions
Sexual Dimorphism in the Human Pelvis
differences in features- those that maximize size of female birth canal (more circular pelvic inlet, wider/greater saciatic notch, wider and less funneled pelvis, larger sub-pubic angle)
Risk of Bipedalism
human mothers have difficulty at birth, human baby must rotate head/body to fit thru, shape of human birth canal and manner of human birth- unique, inversely oval at pelvic inlet
Complications of Human Childbirth
solution- Assisted childbirth, better health supports for expectant mothers
(most diurnal primates)
feed, travel, and sleep in groups
Soliatry Primates
rarely seen with another ind, except when mating/infant dependency
Equipped for Sociality
primate features promote sociality (Elaborate systems of scent marking and detection; Communicative postures; Expressive faces; Diverse vocal repertoires
Primates' advanced social awareness-
(Perceptive to other individuals' reactions/expectations; May even cue individuals for social interactions)
Living in Groups
be tolerant
form relationships
Reproductive Success
From evolutionary perspective, individual's success = # of offspring it contributes to next generation
# of offspring that live to reproduce themselves
Why live in groups
increased ability to detect/defend against predators
improved access to foods
better access to mates
assistance in caring for offspring
Predator Avoidance
selects for group living in diurnal primates
group members gain increased protection, warning systems, DETERRING predators, should the group flee, then any 1 ind. is LESS SUSCEPTIBLE "selfish herd"
Vervet Monkey Calls
different calls for bird/leopard/snake!
diff calls- look into air/hide in bushes for eagle call, stand up look in grass for snake
like words or just sounds? react differently, calls designate enviro feautre and respond accordingly
Improved Defense and Access to Food Resources
Groups actively DEFEND food resources
Individuals may benefit from COMMUNAL KNOWLEDGE or COOPERATIVE FORAGING of food resources
Resource Defense
territory defense (in chimps)
Cooperative Foraging
Access to foods otherwise be inaccessible
Foods shared w/ others in the group
(cape hunting dogs, humans)
Access to potential mates
Living in groups provides contact with potential mates (but only first steps to successful reproduction)
Assistance in Protecting and Rearing Young
advantage of group living
Parental Investment
parental behaviors that increase the probability that offspring will survive
Infant care particularly important aspect of reproductive behavior bc primates give birth to relatively helpless infants
ind that cares for infant but is not a parent
Disadvantages of Group Living
increased comp for food/mates
elevated risk of disease transmission
interference with reproduction
Scramble Competition
occurs when resources CANNOT BE EASILY MONOPOLIZED or defened, so distributed on first come basis
Conteset Competition
direct conflict occurring when access to a resource CAN BE MONOPOLIZED by 1+ ind
Elevated risk of disease transmission
Contact w/ conspecifics- increased exposure to infectious diseases
Ex- gorillas living in social groups have higher rates of illness and mortality from infectious diseases than bachelor gorillas
Interference with Reproduction
newly dominant males will kill infants in group to induce sexual cycling of females
Social Groups Definition
individuals who socialize more frequently among themselves than w/ members of other social units
Exhibit diff behavior towards non-group members
Occupy same home range
Stable Groups
most dirunal primates, cope with enviro and social units while maintaining group cohesion
Fission-Fusion Social Systems
change group composition on reg basis to meet demands of diff situations
Groups are dynamic
change with births, emigration (joining group), immigration (leaving group), death
Types of Primate Social Groups
multi-male, multi-female (45%)
one male, multi-female (34%)
one female, multi-male
one female, one male (4%)
Multi-Male, Multi-Female
>1 adult male and >1 adult female
capuchins, langurs
One Male, Multi-Female
one male interacts with >1 female and immature offspring
black/white colobus, patas monkeys
males unrelated to females (avoid inbreed)
females in group may be closely related or unrelated
One Female, Multi-Male
marmosets, tamarins
One Male, One Female
live together for life
titi monkeys
several social groups aggregate
function of gatherings vary (strategy to maximize ind knowledge of resources, exploit superabundant resource, "fam reunions" or related ind, sig cult events)
Maintain Mult Relationships
interactions w/ kin w/in social group
associations w/ non-kin w/in social group
encounters w/ members of nearby groups
large group sizes- associated with more complex social recognition
Interactions Among Individuals
Social Relationships
content/quality/patterning of interactions
(mother-infant, consort, male-male)
Social Structure
summer of the nature, quality, and patterning of relationships
(Hinde's classic diagram of social structure)
behaviors are acts of help or assistance that benefit others; 4 Types (Comforting- emotional support to others; Informing-useful info for others; Instrumental Helping- Act on behalf of others' goal; Sharing- Giving food/objects to others
Requisites for Prosociality
sensitivity to external stimuli (signals of need, social distance to partner, presence and size of an audience)
intrinsic motivation (reactive- response to request; proactive- absence of request)
2 Components of Instrumental Helping
1. understand other person's beh in terms of goals/intentions (human kid 12-18 months can differentiate purposeful from accident; infer what another trying to achieve without seeing outcome)
2. have motivation to help others (human infant as young as 12 months- comfort victims of distress)
do kids combine understand of others' goals and motivation to help others?
Prosociality in Humans
Has been claimed that humans may differ from other living apes in
1.Sensing the signals of need
2.Presence of audience effects
3.Proactive prosociality
Specific types of prosociality considered uniquely human
Infants willing to help-
multiple times
when costs raised
rewarding wasnt necessary
intrinsic motivation, chimps also willing
More complicated than helping bc involves recruiting others, coordinating your actions to achieve goal, and agreeing about how to deal w/ benefits
Specific Components of Cooperation
rec when need help
actively recruit
aggree actions to perform jointly
rec others' roles in effort to ensure success
How cooperation emerge
culturally acquired? (encourage, reward, socialization process)
natural tendency to be helpful? (basic instinct modified if detect cheaters/ un cooperative people)
Examining Collaborative Abilities in Other Apes
Presented chimps w/ collaboration problems, had to decide:
When to recruit a partner
Which potential partner to recruit
Recruiting the Best Collaborators
Hirata Experimental Setup
Chimpanzee Politics
Although chimps capable of spontaneous cooperation, tolerance and relationships play important role in their performance
detected cheaters
PROACTIVE Prosocial Sharing
Bonobos invite others to join, even when cooperation not required to complete task!
The Deep History of Cooperation
"Therefore, recognizing when collaboration is necessary and determining who is the best collaborative partner are skills shared by both chimps and humans, so such skills may have been present in their common ancestor before humans evolved their own complex forms of collaboration"
Role of Language in Cooperation
Language may be key diff that allows humans to establish intentions and expectations of both parties w/ regard to exchanges
Specific agreements and contracts established
Lacking ability to make specific agreements about future events, nonhumans may be limited to cooperative strategies that generate immediate benefits
Life History Theory
study of how characteristics of an organism's life cycle affect reproduction
focus on trade offs btwn energy expended for numbers and fitness of offspring
Characteristics that impact reprod success
age at maturity
age at reproduction
gestation length
interval btwn births
overall lifespan
Life History: The General Framework
embriotic dev
prenatal stage
fertilized egg
prenatal stage
stage growth from 2-8 weeks
prenatal stage
stage of growth fom 8 weeks til birth
postnatal stage
birth until weaning, up to 3 years in nonindustrial societies
Infant Phase
length varies with body size and phylogeny
Primate infants depend primarily on mothers to meet nutritional needs
Some primate infants dependent on other for transportation needs
Infants not likely to survive death of primary caretakers
Alloparental Care
infant care provided by ind other than parent (Benefits: posibility that this is their infant. est affiliations with mother- access to future mating, gain experience in infant care)
Caregivers provide
defense against predators/aggression
supplemental resources (food sharing)
cotton top tamarins- increase group size decrease in infant mortality
Parent-Offspring Conflict
Mothers selected to stop investing in offspring sooner than offspring selected to accept it
Mother's Perspective on Weaning
sooner that her offspring can find food on its own, sooner so can resume ovulating and reproduce again
Infant's Perspective on Weaning
interested in capturing as much of mother's investment as possible
Resistance to Weaning
Following their mothers
Attempting to suckle
Crying for long time when refused suckling
Throw tantrums when not allowed suckle
Sex Differences in Development
Male and Female primates in the same social group grow up in different ways
Males and females-Have different rates of development. Have different probabilities of dying at different times in their lives. Group members treat them differently
Distance Curve
measure of size over time, such as height or weight over time
(body growth not same from year to year. changes with different stages form infancy to adulthood)
used by parents to track growth of child (2 yrs, 30 lbs, 75th percentile)
Velocity Curve
measure of rates of change in growth over times
rate of growth is highest immediately afterbirth
followed by deceleration during infancy
increase during adolescent period
rate of growth terminates in adulthood
Energy Trade-Off
after maturity is reached, energy expended for growth is used for reproduction
weaning until the end of growth in brain weight, which occurs at 7 years old
from end of childhood to adolescence
(juvenile phase= from weaning to sexual maturity)
compared to other mammals- primates have LONG JUVENILE PERIODS
Extended Juvenile Period
opportunity to learn motor/social skills
gain experience, learn how to be adult (specialized foraging- tool use, predatory detection, repsonse to predators, social skills, fighting abilities)
essential in the proper social/biological development of primates
aid in developing: Motor coordination, Abilities to socially interact with others. Affiliative relationships with peers who may be useful allies in the future
time of sexual maturation and spurt in body growth
(10 yrs old females, 12 yrs old males)
complete physical maturity
Adolescent Growth Spurt
Just prior to sexual maturity- phase of rapid growth (growth spurt)
Timing and magnitude varies among species and btwn sexes
Differences in timing and rates of growth are related to sexual dimorphism
Proces of sexual maturation
hormonally induced physiological, morphological and beh changes
males begin sperm production, dev of 2ndary sex char
females begin ovulating, breasts, sex swell
Adulthood and Aging
Primates mature later and live longer than other mammals of similar body size
Age at maturation and longevity affect REPRODUCTIVE LIFESPANS
Life history trade-offs can equalize time available for reproduction-For examples- greater longevity can compensate for delayed maturation
Fast Life History
reaches maturity EARLY and has LARGE # OF OFFSPRING during rep life
mice mature quickly, lots of offspring
Slow Life History
maturation delayed until later in life span, total # of offspring- lower
orangutans ahve very slow rate of rep
Age at Adulthood
orangutan, chimp, bonobo, gorilla ~10 yrs
human ~21 yrs
Humans live longer
live longer
Human Lifespan
world avg expectancy 67 yrs
(late stone age 50,000-10,000 ya- 33 yrs)
Humans have Long Post-Reproductive Life
long post-rep life
permanent cessation of menstrual cycles, which occurs before the end of the average human life span
Only found in humans (+ 1 species whale)
Post-Menopausal Longevity Hypotheses
Mother Hyp
Grandmother Hyp
Outlive Hyp
Mother Hypthesis
more adaptive later in life for women to expend time and energy insuring the survival of their existing children than to produce more children
Grandmother Hypothesis
post-menopausal women can help their daughter raise children, which increases their inclusive fitness
post-menopausal longevity is simply a result of humans outliving their egg supply
Humans have slow rate of rep
slow rate of rep
Intervals between Births
Primate offspring typically not born until previous mature enough to survive
Interval btwn birth in nonhum apes ~5 yrs
Humans=exception- overlapping births w/o sacrificing quality of parental care
What adaptations have enabled us to achieve this reproductive feat?
Comparing Intervals between Births
Orangutan IBI ~7 years
Gorilla IBI ~4 years
Chimp ~5 years
Humans (Foragers) ~3 years
Extremes in human rep
69 kids
Comparing Human Growth with other Mammals (2 basic diffs)
1. distinct life stages, with long post-reproductive period
2. humans have extended childhood and adolelscent period
Advantages of Prolonged Childhood
physical limits to brain growth in the womb
So best time for brain growth is during first yrs of life but this means that sexual maturity is postponed
Evolutionary advantage to extended childhood and delayed maturation-
Longer childhood allows more time for brain development and learning
Parental Investment
evolutionary explanations of beh focus on maximizing fitness (beh increase prob your DNA will be passed to next gen)
parental beh's that increase prob that offspring will survive
Mother-Infant Bond
Unlike some other mammals, infant primates are helpless at birth
Depend completely on mother's food, warmth and protection to survive
The biological importance of the mother infant bond is both- PHYSICAL in terms of nourishment and protection; SOCIAL in terms of comfort and socialization
mother-infant bond is the STRONGEST bond in primate societies
Learning how to mother
Infants born to first-time mothers may suffer higher mortality, than those born to reproductively experienced mothers
Shown in infant bonobos, tamarins, and mantled howler monkeys
Maternal Styles
Primate mothers interact w/ infants in individualistic ways
mothering techniques can have lasting impacts on infant social development
Some aspects of maternal style seem to be SOCIALLY TRANSMITTED
Harry Harlow
Am. psychologist, Influenced by 1950's research on imp of primary caregiver
Expressed concern about fellow psychologists' lack of interest in love bc considered "improper topic for experimental research"
Love "pervades our entire lives"
Harlow's Surrogate Mothers
rhesus monkeys- Removed infants from mothers, placed in cages w/ "surrogate" mothers, Surrogate made of wire w/ bottle attached, Surrogate made of wire w/ terry cloth wrapped around structure
Importance of Mother-Infant Bond
Harlow showed that maternal care was importnat not only for nutrition but for normal social dev
monkeys deprived of maternal care showed abnormal beh (incapable of sex rep; didnt interact normally with others; aggressive) motherless females didnt know how to care for subsequent offspring- mistreat/reject
Biological Basis of Maternal Care
Although basic mother-infant bond is a part of biological basis of mammals- Specific beh's that are part of bond are LEARNED- Mothers tend to model parental beh's after own mother, research on living primates helps to understand mothering styles observed in human societies
Locomotion: Bipedalism
suspensory with knuckle/fist walking on ground v bipedality
Skulls and Teeth
BIG brains, NO canine dimorph
orang- fistwalk, big brain, canine dimorph
gor- knuckwalk, big brain, canine dimorph
chimp- knuck, big brain, canine dimorph
humans- bipedal, REALLY BIG brain, NO canine dimorph
Diet Comp
hunting/fishing 50% of human diet
chimps- mostly fruit then leaves
Central place foraging
theory describes beh of forager that must return to particular place to consume food, or to share food w/ mate and/or offspring
Essential aspect of human lifestyle
universal human societies
Human Division of Labor, Sharing and Provisioning
chimps: production = consumption
(consume everything get from enviro)
humans: SHARING and PROVISIONING excess food items thru CPF
orang: FRUITS and LEAVES
chimp: FRUITS and LEAVES (meat 4% only)
Life History Humans have extended juvenile period
Opportunity to learn motor skills
Social behaviors
Humans have Long Post-Reproductive Life
Mother, grandmother, outlive egg supply
Life History and Reproduction
Orangutan (Extended juvenile period)
Gorillas (Extended juvenile period)
Chimp (Extended juvenile period)
Humans (foragers) (Extended juvenile period)
Active teaching, Long post-rep life
Social Behavior
Orangutan= Solitary, come together to mate, mother care for young; Loose fission-fusion
Gorillas= 1 male, multi-female
Chimps/bonobos= Multi-male, multi-female
Humans= Multi-male, multi-female
Human language- most complex form of communication in the animal kingdom
systematic creation and usage of a system of symbols est thru social convention
Humans begin attending to language early in development
By adulthood, know 60,000 words
Language Characteristics
OPEN SYSTEM finite # of sounds can be used to create an infinite # of ideas
DISPLACEMENT lang allows discussion of objects/events not in present
ARBITRARY relationship btwn sounds to objects and ideas must be learned
Cross-Fostering Approach
used to examine whether apes were capable of acquiring/using human languages
Cross-foster= offspring removed from biological parents at birth and raised by surrogates of another species
The Ape in our House
Hayes adopt Viki, speech therapy, 4 words, really bad
Gestural rather than Spoken Language
1960s Gardner adopted Washoe (first nonhuman) for language research
Raised using American Sign Language in natural contexts
Washoe was the first nonhuman to acquire a human language
Washoe used signs spontaneously, appropriately, and in combination
She referred to herself
She used sign in creative ways ("water bird" for duck)
Fouts, Fouts, Washoe and Loulis
Fouts graduate student in "Project Washoe" Gardners transferred Washoe to his care
Est the Chimp and Human Communication Institute in Washington
When he was an infant, Loulis was adopted by Washoe He learned sign language from Washoe and other chimps
Patterson and Koko
Vocab >1,300 signs, understands 2,000 words spoken English
Redwood City, California
On Facebook, YouTube, and Twitter
Meet "Nim Chimpsky"
Herb Terrace, Columbia U. students of raised "Nim Chimpsky"
Name- spoof on Noam Chomsky (foremost theorist of human language structure and grammar)
Taught him American Sign Language in a more experimental context
Terrace also analyzed videos from Project Washoe
Attack on Ape Language Studies
Terrace concluded that linguistic apes were not really linguistic
Apes were-
Learning operant responses to get food
Using signs mostly to request things or food
Producing sentences that were redundant within themselves
Mimicking repsonses from humans
The Rumbaugh Rebuttal
Could apes learn to use something resembling human linguistic symbols?
symbol that represents a word but is not necessarily indicative of the object referenced by the word
developed a keyboard of 384 lexigrams, with controls to show that-
1)Apes can comprehend and use lexigrams
2)Use their lexigrams in a variety of contexts
3)Use symbols spontaneously w/ each other
Kanzi Wamba
Tried to teach a wild-caught bonobo, Matata
Her infant son, Kanzi, spontaneously started to used the lexigram
Similar success has been achieved with other bonobos and common chimps
individual attempts to DEMONSTRATE for another how a goal might be accomplished
teacher ahs the intention of instructing the learner
Active teaching
Teaching can be differentiated form other types of socially-biased learning by ACTIVE PARTICIPATION OF THE INSTRUCTOR
Teacher incurs cost and learner benefits
Active teaching in nonhumas is rare, but may be more likely in complex foraging
Lev Semyonovich Vygotsky
Soviet psychologist, Interested in developmental psych, child development, and education
Theories of child development and learning:
Children construct knowledge
Learning can lead development
Development can not be separated from its social context
Language plays a central role in mental development
Emphasizing the Social Context of Learning
Vygotsky introduced the notion of ZONE OF PROXIMAL DEVELOPMENT
Zone of Proximal Development
distance btwn developmental level as determined by independent problem sovling and the level of potential dev thru problem sovling in collaboration w/ others
Social Context of Learning
Coussi-Korbel and Fragaszy (1995) proposed a model of the relation between social dynamics and social learning-
"Individuals in MORE TOLERANT or GREGARIOUS SOCIAL GROUPS are more likely to learn socially and exhibit behavioral homogeneity"
beh that is shared, learned and socially transmitted
Do apes have cutlure
Population-specific behavioral traditions are one potential indicator that a species engages in some form of social learning or "cultural transmission"
Behaviors that are similar for individuals within a population, but not found in other populations (despite similar opportunities)
Chimp cultures
9 long-term study sites surveyed through correspondence
Different cultural behaviors
Social Behavior
Orangutans (Solitary, Culture??? Social Learning, Symbolic Ability)
Gorilla (1 male, multi-female, Symbolic Ability)
Chimp (Multi-male, multi-female, Culture?? Social Learning, Symbolic Ability)
Humans (foragers) (Multi-male, multi-female, CULTURE, Active Teaching, LANGUAGE)
The idea that natural selection will always provide an opportunity for some members of a species to survive is NOT accurate
Examination of the fossil record shows us that 99% of all past species are extinct
Woolly mammoths had mostly disappeared by the end of the Pleistocene (10,000 ya)
Primate Conservation
nearly 1/3 of extant primates are at risk of going extinct
Conservation Classifications of Primate Taxa
Extinct- 2 primates
Critically endangered- 9%
Endangered- 21%
Vulnerable- 19%
Near threatened -6%
Data Deficient - 13%
Least concern- 32%
Bushmeat Trade (AIDS, zoonotic transmission of SIV-1 from chimps, HIV-1 GROUP M- viruses responsible for great majority of all HIV infections worldwide)
Disease risks (pathogen exchange, from nonhumans to humans)
Conservation Action: Stopping Primate Bushmeat
they're naturally infected with over 40 different SIVs
there's a conceted effort to riase awareness and stop the bushmeat trade in Africa
Conservation Threat: Reduction of Habitat
habitats disappearing
Threat: Mechanized Logging
More than 50% of remaining primate habitats are allocated to timber concessions. Many forests will experience multiple harvests
Sad orangutan video
Conservation Action: Raising Consumer Awareness
Green products, good wood guide, recycle
Palm Oil Cultivation
Increased demand for palm oil is fueling destruction of the rainforest habitats of Sumatran and Bornean orangutans
Palm oil forecast to overtake soybean oil as the most produced and traded edible oil by 2012
Orangutan-Friendly Halloween Candy
"we can find other ways of making cookies. We can't find other ways of making orangutans"