Transcript Chapter 6 Primate Behavior

Chapter 7
Primate Behavior
Chapter Outline
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Primate Field Studies
The Evolution of Behavior
Why Be Social?
Primate Social Behavior
Reproduction and Reproductive
Strategies
Mothers, Fathers and Infants
Importance of Primate Studies
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Modern African apes and humans last
shared a common ancestor between 5
and 8 m.y.a.
Only within the last 4 decades have
nonhuman primates been studied.
Many species, such as arboreal
monkeys have scarcely been studied at
all.
Primate Socioecology
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Socioecology studies the relationship
between social behavior and the natural
environment.
 One assumption is that components of
ecological systems evolved together.
 To understand how one component works, it
is necessary to determine the species
relationships with their environment.
Environmental Factors
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Quality and quantity of foods
Distribution of food resources, water,
predators and sleeping sites
Activity patterns (diurnal, nocturnal)
Relationship with other species
Impact of human activities
Socioecology and Predation
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Environmental factors influence on group size
and structure.
 Multimale and multifemale groups have an
advantage when predation pressure is high.
– Adult males may join forces to attack predators.
– Savannah baboons have been known to kill
domestic dogs and attack leopards and lions.
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Solitary foraging may be due to distribution of
resources or predator avoidance.
Evolutionary Perspective
Natural selection acts on behavior just as
it acts on physical characteristics.
– Behavior is a phenotypic expression and
genes code for specific behaviors.
– Natural selection has a role in shaping
primate behavior.
Criticism of the
Evolutionary Perspective
Little data on:
 The social behavior of large groups of
animals.
 Genetic relatedness through the male
line.
 Assigning reproductive costs and
benefits to particular behaviors.
 The genetics of primate social behavior.
Dominance Status
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Factors that influence status:
– Sex
– Age
– Aggression
– Time in the group
– Intelligence
– Motivation
– Mother’s social position.
Communication
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Raised body hair is an example of an
autonomic response.
Vocalizations and branch shaking are
examples of deliberate communication.
Reassurance is communicated through
hugging or holding hands.
The fear grin, seen in all primates, indicates
fear and submission.
Displays communicate emotional states.
Primate Social Strategies
Affiliative Behaviors
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Grooming reinforces social bonds.
Hugging, kissing and grooming are all
forms used in reconciliation.
Relationships are crucial to nonhuman
primates and the bonds between
individuals can last a lifetime.
Patterns of Reproduction
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In most primate societies, sexual behavior is
tied to the female’s reproductive cycle.
 Permanent bonding is not common among
nonhuman primates.
 Male and female Bonobos may mate even
when the female is not in estrus, a behavior
that is not typical of chimpanzees.
Reproductive Strategies
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Behavioral patterns that contribute to
individual reproductive success.
Primates produce only a few young in
whom they invest a tremendous amount
of parental care. (k –selected)
Male competition for mates and mate
choice in females are both examples of
sexual selection.
Mothers and Infants
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The basic social unit among all primates is
the female and her infants.
 Except in species in which monogamy or
polyandry occur, males do not participate in
rearing offspring.
 Monkeys raised without a mother were not
able to form lasting affectional ties.
 The mother-infant relationship is often
maintained throughout life.
Factors Influencing Evolution
of Primate Behavior