Anthropology 101 Chapter 6

lemurs, lorises, tarsiers, monkeys, and apes

Arboreal settings

Rise of angiosperms (flowering plants)

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.

Omnivorous

Incisors for biting and cutting; premolars and molars for chewing and grinding

• Dental formula
• ¤Old World anthropoids have two incisors, one canine, two premolars, and three molars on each side in
• both upper and lower jaws: 2.1.2.3 (32 teeth total)

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

A horse’s front foot, homologous with a human hand, has undergone reduction from 5 digits to one.

While raccoons are capable of considerable manual dexterity and can readily pick up small objects with one hand, they have no opposable thumb.

Many monkeys are able to grasp objects with an opposable thumb, while others have very reduced thumbs.

Quadrupedal, walk on all fours

Vertical clinging and leaping

Brachiation

Knuckle walking

Skeleton of a brachiator (gibbon).

Chimpanzee

Color vision is a characteristic of diurnal primates.

Nocturnal primates lack color vision.

Depth perception is made possible by eyes positioned forward on the front of the face.

Primates have a decreased reliance on the sense of smell.

The condition whereby visual images are superimposed on one another.

• This provides for depth perception, or the perception of the external environment in three
• dimensions.

Stereoscopic vision is partly a function of structures in the brain.

Vision characterized by overlapping visual fields provided for by forward-facing eyes.

Binocular vision is essential to depth perception.

Two halves of the cerebrum that are connected by a dense mass of fibers.

The cerebrum  is the large rounded outer portion of the brain.

• ¤Reliance on olfaction
• ¤Laterally placed eyes
• ¤Shorter gestation and maturation
• ¤Dental specialization called the "dental comb”

The moist, fleshy pad at the end of the nose seen in most mammals.

The rhinarium enhances an animal’s ability to smell.

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).

Found in tropical forests and woodlands of India, Sri Lanka, southeast Asia, and Africa.

• Characteristics:
• ¤Nocturnal
• ¤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

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.

¤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

Represent about 85% of all primate species.

Divided into two groups separated by geography and several million years of evolutionary history:

¤ New World monkeys

¤ Old World monkeys

70 species almost exclusively arboreal.

Found in southern Mexico and Central and South America.

Two families: Callitrichidae and Cebid

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 intosubfamilies, the cercopithecines and the colobines.

The subfamily of Old World monkeys that includes baboons, macaques, and guenons.

Omnivorous, cheek pouches, majority found in Africa

The subfamily of Old World monkeys that includes the African colobus monkeys and Asian langurs.

Differences in physical characteristics between males and females of the same species.

For example, humans are slightly sexually dimorphic for body size, with males being taller, on average, than females of the same population.

¤Larger body size

¤Absence of a tail

¤Shortened trunk

¤More complex behavior

¤More complex brain

¤Increased period of infant development

Found in heavily forested areas of Borneo and Sumatra.

Almost completely arboreal. 

males = 200 lbs; females = 100 lbs

Pronounced sexual dimorphism.

Solitary

Principally frugivorous (fruit-eating).

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.

Confined to forested areas of western and eastern equatorial Africa

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.

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.

The only living species in the family Hominidae.

Human teeth are typical primate teeth.

Dependence on vision for orientation to the world

Flexible limbs and grasping hands

Omnivorous diet

Cognitive abilities are the result of dramatic increases in brain size.

Bipedal

Mental capacity; ability to learn, reason, or comprehend and interpret information, facts, relationships, and meanings.

The capacity to solve problems, whether through the application of previously acquired knowledge or through insight.

• ¤Habitat destruction
• ¤Hunting for food
• ¤Live capture for export or local trade

Over half of all living primates are endangered, many face immediate extinction.

Living nonhuman primates represent a lineage that goes back approximately 60 million years.

• They can provide us with information about how evolutionary processes have produced the diversity
• we see in our own lineage today.

• We can identify genetic causes for certain conditions (such as AIDS) that humans are
• susceptible to but chimpanzees are able to resist.

Answer: b

A highly developed sense of smell is NOT a primate characteristic.

Answer: d

Binocular vision in primates contributes to stereoscopic vision

Answer: c

Tarsiers do not live in groups of 10-12 individuals.