The Living Primates

Outline Common primate traits Classification of primates The various primates Distinctive hominid traits Explanations of variable primate adaptations

Why Study Primates? Adaptation to environment Anatomical & behavioral Chimpanzee, Bonobo, Gorilla

Common Primate Traits Primate traits share all of the traits of mammals covered with hair, warm-blooded, and give birth to live young who are dependent upon parent(s) Physical features Social features

Common Primate Traits – Physical Features Rotating forearms Clavicle Omnivorous Grasping hands & opposable thumbs No claws Visual developments Large brain relative to body size Aspects of the reproductive system (single births, development of fetus at birth) Skeletal attributes that correspond to an arboreal existence

Some Common Primate Traits Figure 4-1

Common Primate Traits – Social Features Diurnal Long dependency Group care & father involvement Importance of play primates learn physical and social skills useful as adults Learning from others imitation versus independent learning Harlow’s monkeys primates learn physical and social skills useful as adults

Dependency Periods of Primate Offspring Figure 4-2

Classification of Primates There are two suborders in the order Primates Prosimians lemurs, tarsiers, and lorises Anthropoids New World monkeys, Old World monkeys, lesser apes, great apes, and humans

Simplified Classification of the Living Primates Figure 4-3

The Various Primates Prosimians Anthropoids Greater reliance on smell than anthropoids (and thus longer snout), mobile ears, whiskers, fixed facial expressions Anthropoids Rounded braincase; nonmobile outer ears; smaller, flat faces; dexterous hands. Anthropoids are divided into groups based on characteristics of their noses: platyrrhines (New World monkeys) and catarrhines (Old World monkeys, apes and humans)

Prosimians Lemurlike forms Lorislike forms Tarsiers Madagascar and the Comoro Islands give birth to a single offspring, are quadrupeds (though some are vertical clingers and leapers), and are nocturnal Lorislike forms Southeast Asia and sub-Saharan Africa arboreal, nocturnal, and generally give birth to a single offspring Tarsiers The Philippines and Indonesia nocturnal and are insectivores and carnivores controversy as to whether tarsiers should be classified into prosimians or anthropoids

Anthropoids New World monkeys Old World monkeys The Hominoids Platyrrhines, some have prehensile tails, and all are arboreal Old World monkeys Catarrhines, and vary in habitat from being arboreal to terrestrial depending upon the species The Hominoids Apes and humans Large brains; long arms; short broad trunks; no tail; wrist, elbow, and shoulder joints with a greater range of movement

Features of Platyrrhines and Catarrhines Figure 4-4

Distinctive Hominid Traits Physical traits Behavioral abilities

Physical Traits of Hominids Bipedalism Large and complex brain Opposable thumb Good hand-eye co-ordination Chin

Behavioral Abilities Toolmaking Language Other Hominid traits only hominids are habitual toolmakers and create tools to make other tools Language Symbolic, spoken language Other Hominid traits hunt very large animals completely terrestrial longest dependency period of any other primate division of labor

Explanations of Variable Primate Adaptations Body size Determined by three factors time of day a species is active where it is active (arboreal or terrestrial) kind of food eaten Relative brain size ratio of brain size to body size Group size nocturnal (single or pairs) or diurnal (larger groups) large groups can offer protection the amount and density of food resources

Reflection How could you infer that a fossil primate lived in the trees? Why are primates so smart? Under what conditions would the ability to communicate be adaptive? Why are humans immature for so long?