1. An Overview of the Primates
Chapter 6
An Overview of the Primates

2. Chapter Outline Characteristics of Primates Primate Adaptations
Primate Classification
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. 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

6. 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.
The brain has expanded in size and become increasingly complex.

7. Binocular Vision in Primates

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

9. 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.

10. Arboreal Hypothesis
Arboreal 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.

11. 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.

12. 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.

13. Primate Diet and Teeth
Generally omnivorous, reflected in their generalized dentition.
Most eat a combination of fruits, leaves, and insects.
Most have four types of teeth: incisors, canines, premolars and molars.

14. Primate Locomotion
Most are quadrupedal, using all four limbs in their locomotion.
Arm swinging is found among the apes.
Prehensile tails, found only among the new world monkeys, are used as an aid to locomotion.

16. Alternative Classifications of Great Apes and Humans
Revised classification
(more evolutionarily accurate)
Traditional
classification
Great apes—separate family (Pongidae)
Orangutan
Gorilla
Chimpanzee
Bonobo
One family only (Hominidae), including all large-bodied apes and humans; more detailed distinctions made at lower taxonomic categories
Humans—separate family (Hominidae)

17. 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”

18. 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).

19. Lorises
Found in tropical forests and woodlands of India, Sri Lanka, southeast Asia, and Africa.
Characteristics:
Use a climbing 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.

20. Tarsiers
Small nocturnal primates found on the islands of southeast Asia.
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.

21. 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

22. 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

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

24. 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.

25. 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.

26. 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.

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

28. 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”.

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

30. 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.

31. 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.

32. 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.

33. 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

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

35. Endangered Primates
Over half of all living primates are endangered, many face immediate extinction.
Three reasons:
Habitat destruction
Hunting for food
Live capture for export or local trade

36. 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.

37. Quick Quiz

38. 1. Which of the following is NOT a primate characteristic?
stereoscopic vision
highly developed sense of smell
orthograde or upright posture
prehensility

39. Answer: b
A highly developed sense of smell is NOT a primate characteristic.

40. 2. Binocular vision in primates contributes to
color vision.
lateral vision.
panoramic vision.
stereoscopic vision.

41. Answer: d
Binocular vision in primates contributes to stereoscopic vision.

42. 3. Which of the following is NOT true of tarsiers?
They are nocturnal.
They are insectivorous.
They live in groups of individuals.
They can rotate their heads almost 180 degrees.

43. Answer: c
Tarsiers do not live in groups of individuals.

44. 4. The _________________ is the largest living primate.

45. Answer: gorilla
The gorilla is the largest living primate.

46. 5. Which of the following is NOT a reason that nonhuman primates are endangered?
habitat destruction for logging, mining, and agricultural land
hunting for food
live capture for either the exotic pet trade or biomedical research
establishment of biological reserves

47. Answer: d
The establishment of biological reserves is NOT a reason that nonhuman primates are endangered.