Primates as Mammals
Primates as Mammals
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Primates, are intelligent animals whose young are born live and nourished with
milk from their mothers.
Nursing their young is an important part of the mammalian tendency to invest high
amounts of energy into rearing relatively few young.
Their skeleton and teeth resemble those of other mammals
Mammals possess precise numbers of specialized teeth, each with a particular
shape characteristic of the group.
Primate Characteristics
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Primates developed characteristics as adaptations to insect predation and life in
the trees:
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A reduction in the number and size of teeth.
Binocular stereoscopic vision (depth perception) and a reduced sense of
smell.
An intensified sense of touch.
An enlarged, responsive cerebral cortex.
Changes to the skeleton included a reduction of the snout, an enlargement
of the braincase, and adaptations for upright posture and flexibility of limb
movement.
Brachiation
Using the arms to move from branch to branch, with the body hanging
suspended beneath the arms.
Chimpanzee Brachiation
The Primate hand
Prehensile hands
– O.W. monkeys – prehensile tale
Opposable thumb
Nails rather than claws
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Living Primates
There are five natural groupings of contemporary primates:
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Lemurs and lorises
Tarsiers
New World monkeys
Old World monkeys
Apes
Prosimians and Anthropoids
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Lemurs, lorisers, and tarsiers are grouped together by some primatologists as
prosimians
Monkeys, apes, and humans are grouped together as anthropoids
Lemurs and Lorises
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The living primates whose anatomy and behavior most closely resemble those of
the earliest primates.
Tarsiers
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Tarsiers are nocturnal insectivores
They exhibit characteristics not found in other primates such as:
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Large immobile eyes
The ability to turn their heads 180 degrees.
New World Monkeys
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All are arboreal with long tails.
All are diurnal but one
Some New World monkeys possess prehensile or grasping tails, which they use as
a fifth limb.
Old World Monkeys
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Are the most widely distributed living primate (with the exception of humans)
They possess nonprehensile tails and may live on the ground or in trees.
They use quadrapedal locomotion on the ground
Baboons are studied more than any other O.W. monkey
Apes
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The closest living relatives we humans have in the animal world.
They include gibbons, siamangs, orangutans, gorillas, chimpanzees, and bonobos.
bonobos, chimpanzees, and gorillas are closer to humans (hominidae).
Bonobo clip
Primate Behavior
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Primates are social animals and most species live and travel in groups.
Males and females can be organized into dominance hierarchies
Dominance hierarchies determine access to resources (food, mates)
Aggression is used to assert & challenge dominance,
and can be directed outside the group
Tool Use
A tool may be defined as an object used to facilitate some task or activity.
From adults, juveniles learn to use a variety of tools and substances for various
purposes.
Innovations made by one individual may be adopted by other animals,
standardized, and passed on to succeeding generations.
Chimpanzee Tool Use
Chimpanzee tool-use
Grooming
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The ritual cleaning of another animal to remove parasites and other matter from its
skin or coat
Grooming also has a social function
It can be a gesture of friendliness, closeness, appeasement, reconciliation, or even
submission.
Sexuality
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Sexual interaction among chimpanzees generally takes place only when a female
is in estrus.
In bonobos, constant swelling of the female’s genitals suggests constant estrus.
This results in a concealed ovulation, much as we find in human females:
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Bonobos separate sexual activity from the biological task of reproduction.
Sex between both opposite and same-sex individuals serves as a means of
reducing tensions.
Communication
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Primates have elaborate systems of communication based on vocalizations and
gestures.
Chimpanzees use facial expressions to convey emotional states.
It is now clear that all of the great ape species can develop language skills to the
level of a 2-to-3 year-old human child.
Culture
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Our nearest primates relatives, the apes, have learned, socially shared practices
and knowledge.
There is variation in tool use and flexibility in patterns of social engagement that
suggest the presence of culture.