Chapter 6

1. Chapter 6 An Overview of The Primates

2. Chapter Outline • Characteristics of Primates • Primate Adaptations • Primates Classification • A Survey of the Living Primates • Endangered Primates

3. Primates As Mammals • There are approximately 190 species of nonhuman primates • Primates belong to: • Vertebrate class - Mammalia • Subgroup of placental mammals.

4. Characteristics of Primates • Fur (body hair) • Long gestation followed by live birth • Homeothermy, the ability to maintain a constant body temperature • Increased brain size • Capacity for learning and behavioral flexibility.

5. Binocular Vision in Primates

6. Primate Limbs • A tendency towards erect posture. • Hands and feet possess grasping ability. • Features of the hands and feet: • 5 digits on hand and feet • Opposable thumb • partially opposable great toe • Tactile pads enriched with sensory nerve fibers at the ends of digits

7. Dental Formulae

8. Primate Senses and the Brain • Color vision is a characteristic of all diurnal primates, nocturnal primates lack color vision. • Depth perception is made possible by eyes positioned forward on the front of the face. • Decreased reliance on the sense of smell (olfaction). • The brain has expanded in size and become increasingly complex.

9. Primate Maturation • Longer periods of gestation • Reduced numbers of offspring • Delayed maturation • Extension of the entire life span.

10. Primate Learning and Behavior • Have a greater dependence on flexible, learned behavior. • Tend to live in social groups. • Males are permanent members of many primate social groups, a situation unusual among mammals.

11. Arboreal Hypothesis • Arboreal (tree) living was the most important factor in the evolution of primates. • Prehensile hand is adapted to climbing in the trees. • A variety of foods led to the omnivorous diet and generalized dentition.

12. Visual Predation Hypothesis • Primates may have first adapted to shrubby forest undergrowth and the lowest tiers of the forest canopy. • Forward facing eyes enabled primates to judge distance when grabbing for insects. • Flowering plants may have influenced primate evolution.

13. Primate Habitats • Most live in tropical or semitropical areas of the new and old worlds. • Most are arboreal, living in forest or woodland habitats. • No nonhuman primate is adapted to a fully terrestrial environment; all spend some time in the trees.

14. Primate Diet and Teeth • Generally omnivorous, reflected in their generalized dentition. • Most eat a combination of fruits, leaves, and insects. • Some primates kill and eat small mammals. • Some primates are dietary specialists on leaves. • Most have four types of teeth: incisors, canines, premolars and molars.

15. Primate Locomotion • Most primates are quadrupedal, using all four limbs in their locomotion. • Arm swinging is found among the apes. • Siamangs of southeast Asia use this exclusively. • Monkeys that use a combination of leaping and arm swinging are termed semibrachiators. • Prehensile tails, found only among the new world monkeys, are used as an aid to locomotion.

16. Human and Chimpanzee Chromosomes • Human chromosome2 has banding patterns that correspond to chimpanzee chromosomes 12 and 13. • This suggests that human chromosome 2 resulted from the fusion of ape chromosomesduring the course ofhominid evolution.

17. Revised PartialClassification of the Primates.

18. Alternative Classifications of Great Apes and Humans

19. Prosimians • The most primitive of the primates. • Characteristics: • Reliance on olfaction • Laterally placed eyes • Shorter gestation and maturation periods • Dental specialization called the "dental comb”

20. Lemurs • Found on the island of Madagascar and other islands off the coast of Africa. • Extinct elsewhere in the world. • Characteristics: • Larger lemurs are diurnal and eat vegetable foods: fruit, leaves, buds, and bark. • Smaller lemurs are nocturnal and insectivorous (insect -feeding).

21. GeographicalDistribution of Modern Lemurs

22. Lorises • Found in tropical forests and woodlands of India, Sri Lanka, southeast Asia, and Africa. • Characteristics: • Use a climbing form of quadrupedalism. • Some are insectivorous; others supplement their diet with fruit, leaves, gums, and slugs. • Females frequently form associations for foraging or in sharing the same sleeping nest.

23. Tarsiers • Small nocturnal primates found on the islands of southeast Asia. • Characteristics: • Eat insects and small vertebrates which they catch by leaping from branches. • Basic social pattern appears to be a family unit consisting of a mated pair and their offspring.

24. Anthropoids(Monkeys, Apes and Humans) • Common traits: • Larger brain and body size • Reduced reliance on the sense of smell • Greater degree of color vision • Bony plate at the back of the eye socket • Different female reproductive anatomy • Longer gestation and maturation periods • Fused mandible

25. Monkeys • Represent about 70% of all primate species. • Divided into two groups separated by geography and several million years of evolutionary history: • New world monkeys • Old world monkeys

26. New World Monkeys • Almost exclusively arboreal. • Found in southern Mexico and central and south America. • Two families: Callitrichidae and Cebid

27. New World Monkeys: Callitrichidae • Give birth to twins • Live in families composed of a mated pair or a female and two adult males, plus the offspring. • Males are involved with infant care.

28. New World Monkeys: Cebid • Possess prehensile tails. • Most live in groups of both sexes and all ages. • Others live as monogamous pairs with subadult offspring.

29. Old World Monkeys • Habitats range from tropical forests to semiarid desert to snow-covered areas in Japan and china. • Characteristics: • Most quadrupedal and arboreal • All belong to the Cercopithecidae family: • Divided into subfamilies, the cercopithecines and the colobines.

30. Geographical Distribution of Modern Old World Monkeys.

31. Hominoids (Apes and Humans) • Characteristics distinguishing hominoids from monkeys: • Larger body size • Absence of a tail • Shortened trunk • More complex behavior • More complex brain and enhanced cognitive abilities • Increased period of infant development and dependency

32. Gibbons and Siamangs • Found in the tropical areas of southeast Asia. • Adaptations for brachiation may be related to feeding while hanging from branches. • Diet is largely fruit with leaves, flowers, and insects. • Basic social unit is a monogamous pair and their offspring. • Males and females delineate their territories with whoops and “songs”.

33. Orangutans (Pogo pygmaeus) • Found in heavily forested areas of Borneo and Sumatra. • Almost completely arboreal. • Large • males = 200 pounds • females = 100 pounds • Pronounced sexual dimorphism. • Solitary • Principally frugivorous (feed-eating).

34. Geographical Distributionof Modern African Apes

35. Gorillas (Gorilla Gorilla) • Largest of the living primates. • Confined to forested regions of central Africa. • Males can weigh up to 400 pounds, females 200 pounds. • Primarily terrestrial, using a posture called “knuckle –walking”. • Groups consist of one large silverback male, a few adult females, and their subadult offspring.

36. Chimpanzees (Pan Troglodytes) • Found in equatorial Africa. • Anatomically similar to gorillas particularly in limb proportions and upper-body shape. • Locomotion includes knuckle-walking on the ground and brachiation in the trees. • Eat a variety of plant and animal foods. • Large communities of as many as 50 individuals.

37. Bonobos (Pan paniscus) • Only found in an area south of the Zaire river. • Population is believed to only number a few thousand individuals. • Exploit the same foods as chimps, including occasional small mammals. • Male-female bonds constitute the societal core. • Sexuality includes frequent copulations throughout the female's estrous cycle.

38. Humans (Homo Sapiens) • The only living species in the family Hominidae. • Human teeth are typical primate teeth. • Dependence on vision for orientation to the world

39. Humans (Homo Sapiens) • Flexible limbs and grasping hands • Omnivorous diet • Cognitive abilities are the result of dramatic increases in brain size. • Bipedal

40. Endangered Primates • Over half of all living primates are endangered, many face immediate extinction • Most primates live in tropical rain forests that are being destroyed for their natural resources. • Some primates are hunted for their meat. • Others are victims of the exotic pet trade.

41. Tropical Rain Forests of the World (Before Recent Massive Destruction)

42. Hunting of Primates • In West Africa the most serious problem is hunting to feed the growing human population. • Estimated that thousands of primates, are killed and sold for meat every year. • Primates are also killed for commercial products.

43. Conservation Efforts • Many developing countries have designated areas as national parks or reserves. • Private organizations, such as the rain forest information center in Ecuador, have set up biological reserves. • Through conservation and educational programs, primate species may have a chance at escaping extinction.