MONKEYS AND GREAT APES

Primates

Why study primates?

Social behavior offers clues to human behavior. Many ‘human’ behavioral traits are seen in primates. Examples?

Behavioral analysis combined with morphological comparisons allow us to determine probable behavior of human ancestors. Ex: Pelvic structure and bipedalism

Chimp – quadrupedal Human – bipedal Early hominids – semi-bipedal

Continuum is formed: apehominidhuman

General Characteristics

Generalized anatomy (with some exceptions)Flexible and diverse behaviorEarliest members of group were nocturnal

and arborealPresent members exhibit all sorts of lifestylesMost species are highly social (exception is

Oranguatan)Large brain size and excellent vision are

trademarks of primatesLong gestation and developmental period.

Methods of Study

Researchers study: Biology Behavior Evolutionary History

Primates are studied in zoos, research colonies/labs and in the wild. Also study extinct primates. Captive – test ability of primates (ASL, art, logic, tool use/puzzles,

etc.) Wild – ‘natural’ behavior (minimize disruption).

Ethical questions? Labs – humaneness, removal from social groups, etc. Wild – does tolerance of human observers make animal more

vulnerable? Can you think of other issues?

Primate images

• http://www.primates.com/• http://tolweb.org/Primates/15963

Alternate Classification

Using anatomical evidence creates Prosimii – Lemur, Loris, Tarsier Anthropoidea – Platyrrhini (NWM) & Catarrhini

(OWM, etc.)Using molecular evidence creates

Strepsirhini – Lemur & Loris Haplorhini - Platyrrhini (NWM) & Catarrhini (OWM,

etc.) and TarsiersNote alternate positioning of TarsiersGroupings tend to divide into nocturnal &

arboreal vs. diurnal & terrestrial

Morphology

Nails and pads – gripDexterityBinocular (visual fields overlap) and

stereoscopic vision (nerve info integrated) Lemurs/Lorises reflect light of back of eye

Varied dentition for varied dietSmell is reduced in importanceIncrease in brain size (cerebral hemispheres)

Leads to flexibility in behavior/rapid adaptability

Morphology

Foramen magnum movedClavicle

larger in apes and OWM, arms hang at sides Smaller in NWM , arms more forward

Scapula – allows for brachiationTailsOpposable toes, semi-opposable thumbs

Behavior

Group dynamics Natal groups Dominance heirarchies (some patriarchal, some matriarchal)

Pair bondingGroomingSexual behavior, monogamy (rare), cheatingRange of developmental/dependency times

Short for lemurs, etc. long for apesPlayCommunication – vocalization, gestures, postures,

trail markers in bonobos

Learning

High level of learning abilityTechniques are shared with peers and

offspring Usually technique is acquired by ‘aping’ another

individual Examples: using rocks to smash nuts, ant fishing with

twigs, salting tubers.Hunting

Chimps – organized raiding parties, also cannibalism