PrimatesBiological Anthropology

Humans as Primates

In order to understand the place of humans in nature, it is first necessary to understand the group of mammals to which humans belong– the primates

Methods of Classification May have inherited the trait form a

common ancestor Humans and monkeys both have 5 digits on

each limb because they inherited this trait from a distant common ancestor

The two species may have developed the same trait independently in their evolution The canary and bat are both small animals

capable of flight because their species evolved flight independently

Homologous traits: traits that show similar structure but may or may not show the same function Arm bones of a human, bird and whale

Analogous traits: traits that have the same function but not the same structure Wings of a bird and a flying insect

Primitive traits: trait has been inherited from an earlier form

Derived: traits that have changed from an ancestral state

Example- 1st mammals had 5 digits on each hand and foot. Humans have retained this condition. Horses have developed a single digit (toe).

Human Taxonomy Kingdom: Animal Phylum: Chordata

Subphylum: Vertebrata Class: Mammals

Reproduction: placental mammals Parental Care: prenatal and postnatal patterns Temperature Regulation: homoiotherms Teeth: deciduous teeth/permanent teeth▪ 4 types: incisors, canines, premolars, molars

Skeletal structure: orientation of limbs of 4legged mammals are tucked under body

Behavior: larger forebrain which includes cerebrum Order: Primates

Primate Characteristics

Many features are related to living in trees

2 most important ability to use hands and feet to grasp

branches Ability to perceive distance and depth

Prehensile (capable of grasping) hands and feet Expanded tactile pads Generalized skeletal structure that can be used

in a variety of ways Binocular stereoscopic vision (eyes are located

on front of skull so vision overlaps) Larger, more complex brains associated with

learning, intelligence, body control, and coordination

Small number of offspring, strong mother-infant bond, extended period of growth, variable paternal care

Social creatures- but social structures vary greatly

Social groups Solitary group Monogamous family group Polyandrous group Uni-male group Multimale/multifemale group (most common

non-human primate group) Social organization by dominance (non-

human)

Prosimians “before simians” (monkeys and apes) More primitive Usually lack one or more primate characteristic

(i.e lack color vision) Rely more on smell Brains are generally smaller relative to body size Many are nocturnal All living species are found in Old World 3 different groups:

Lorises- small, solitary, nocturnal in Asia and Africa Tarsiers- small, solitary, nocturnal in Indonesia Lemurs- biologically and socially diverse

Tarsier Lemur

Loris

Anthropoids

Monkeys and hominoids (apes and humans)

Generally larger bodies Larger and more complex brains Rely more on visual abilities More complex social structures Almost all diurnal Both arboreal and terrestrial species Found in Old World and New World

Monkeys Tails! Smaller brains relative to body size Quadrapedal Arms and legs similar length New World

Prehensile tails and four more premolars More proficient in acrobatic agility

Old World Biochemically and physically more similar to humans

(i.e. same number of teeth) More adaptable to different environments (rainforest,

savanna, snowy mountains)

Hominoids

Do not have tails Larger than monkeys Brain is more complex and larger

than monkeys Invest the most time in raising their

young Can raise arms above head Anatomy allows different type of

movement from monkeys- adept at climbing and hanging from branches- suspensory climbers

3 Categories of Hominoids Lesser apes Great apes Humans

Lesser Apes: Gibbons and Siamangs Smallest of the living apes Usual form of movement is

brachiating (hand-over-hand swinging from branch to branch)

Live in tropical rainforests of SE Asia

Diet primarily includes fruits supplemented by leaves

Social group is a monogamous family structure (adult male, adult female, and offspring)

Great Apes (Asia): Orangutans

Males larger than females

Agile climbers and hangers

Arboreal Uses fist-walking

for moving on the ground

Lives in tropical rainforest

Diet consists of mostly fruit (vegetarian)

Solitary social group structure and polygamous

“Man of the Forest”

Great Apes (Africa): Gorillas Largest living primate Found only in equatorial Africa Males larger than females Males have have larger canine teeth and large

crests of bone on top of skulls Most have blackish hair, but some mature males

have silver gray hair on backs “silverbacks” Predominately terrestrial Use knuckle-walking to move about on all fours Arms longer than legs Live in small social groups (about a dozen)- one

adult male, several females and offspring

Silverback

Great Apes (Africa): Chimpanzees Live mostly in African rainforests Slight sexual dimorphism Knuckle walkers Terrestrial and arboreal Diet consists of mostly fruit; some leaves, seeds,

nuts, insects, and meat Have been observed hunting in planned

coordinated groups Live in large communities of 50 or more where

males are dominant over females Show great variation in facial features and

physical appearance

Great Apes (Africa): Bonobos “pygmy chimpanzee” Longer legs, higher center

of gravity, narrower chest than chimpanzee

Frequent knuckle walkers Walk upright more easily Found only in a restricted

rain forest region in Zaire Diet consists of mostly fruit

and some plants Live in large social groups

in which females are dominant

Sex play used as a method of peacekeeping