Download Chapter 5 Overview of Living Primates

Chapter 5
Overview of Living
Primates
Chapter Outline
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Primates as Mammals
Characteristics of Primates
Primate Adaptations
Survey of the Living Primates
Endangered Primates
Primates As Mammals
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There are approximately 190 species of
nonhuman primates
Primates belong to:
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Vertebrate class - Mammalia
Subgroup of placental mammals.
Characteristics of Primates
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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.
Primate Limbs
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A tendency towards erect posture.
Hands and feet possess grasping ability.
Features of the hands and feet:
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5 digits on hand and feet
Opposable thumb
partially opposable great toe
Tactile pads enriched with sensory nerve fibers at
the ends of digits
Primate Senses and the Brain
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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.
Primate Maturation
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Longer periods of gestation
Reduced numbers of offspring
Delayed maturation
Extension of the entire life span.
Primate Learning and Behavior
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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.
Arboreal Hypothesis
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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.
Visual Predation Hypothesis
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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.
Primate Habitats
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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.
Primate Diet and Teeth
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Generally omnivorous, reflected in their
generalized dentition.
Most eat a combination of fruits, leaves, and
insects.
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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.
Primate Locomotion
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Most primates are quadrupedal, using all four
limbs in their locomotion.
Arm swinging is found among the apes.
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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.
Prosimians
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The most primitive of the primates.
Characteristics:
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Reliance on olfaction
Laterally placed eyes
Shorter gestation and maturation periods
Dental specialization called the "dental comb”
Lemurs
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Found on the island of Madagascar and other
islands off the coast of Africa.
Extinct elsewhere in the world.
Characteristics:
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Larger lemurs are diurnal and eat vegetable foods:
fruit, leaves, buds, and bark.
Smaller lemurs are nocturnal and insectivorous
(insect -feeding).
Lorises
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Found in tropical forests and woodlands of
India, Sri Lanka, southeast Asia, and Africa.
Characteristics:
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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.
Tarsiers
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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.
Anthropoids
(Monkeys, Apes and Humans)
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Common traits:
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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
Monkeys
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Represent about 70% of all primate species.
Divided into two groups separated by
geography and several million years of
evolutionary history:
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New world monkeys
Old world monkeys
New World Monkeys
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Almost exclusively arboreal.
Found in southern Mexico and central and
south America.
Two families: Callitrichidae and Cebid
New World Monkeys: Callitrichidae
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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.
New World Monkeys: Cebid
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Possess prehensile tails.
Most live in groups of both sexes and all ages.
Others live as monogamous pairs with
subadult offspring.
Old World Monkeys
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Habitats range from tropical forests to semiarid
desert to snow-covered areas in Japan and
china.
Characteristics:
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Most quadrupedal and arboreal
All belong to the Cercopithecidae family.
Divided into subfamilies, the cercopithecines and
the colobines.
Hominoids (Apes and Humans)
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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
Gibbons and Siamangs
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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”.
Orangutans (Pogo pygmaeus)
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Found in heavily forested areas of Borneo and
Sumatra.
Almost completely arboreal.
Mmales = 200 pounds, females = 100 pounds
Pronounced sexual dimorphism.
Solitary
Principally frugivorous (feed-eating).
Gorillas (Gorilla Gorilla)
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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.
Chimpanzees
(Pan Troglodytes)
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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.
Bonobos (Pan paniscus)
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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.
Humans (Homo Sapiens)
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The only living species in the family
Hominidae.
Human teeth are typical primate teeth.
Dependence on vision for orientation to the
world
Humans (Homo Sapiens)
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Flexible limbs and grasping hands
Omnivorous diet
Cognitive abilities are the result of dramatic
increases in brain size.
Bipedal
Endangered Primates
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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.
Hunting of Primates
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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.
Conservation Efforts
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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.