Knowt 7.1 - Primate Behaviors

Part 1 - Behavioral Ecology, Social Structure, Social Behaviors

Why do anthropologists study primates?

1. Nonhuman primates are our closest relative.

2. To develop models or hypotheses.

Behavior

Anything an organism does in response to stimuli

Ecology

The study of the relationships between organisms and their environment.

Behavioral Ecology

The study of how ecological factors selected for or against particular behaviors

Primary principles of behavioral ecology:

1. Biological organisms evolved together.

2. Behaviors are adaptations.

3. Behaviors are phenotypes.

4. Behaviors have evolved.

Primary Behavioral Ecology Questions?

1. How does behavior influence an individual’s fitness?

2. How do behaviors drive the evolution of populations or groups?

3. How do ecological factors shape the evolutionary development of specific behaviors?

Difference between innate and learned behavior?

1. Behavioral genetics examines relationship between genes and behavior

2. No one-to-one relationship between genes and behavior (usually a mix of the two)

3. In vertebrates, especially placental mammals, behavior is learned

Social Structure

The composition and size of primate groups and the dynamics between individuals within.

Factors influencing social structure include (11 types)

1. Body Size

2. Basal Metabolic Rate

3. Diet

4. Resource distribution

5. Predation

6. Dispersal

7. Life Histories 

8. Strategies

9. Distribution and type of sleeping sites

10. Activity Patterns

11. Human Activities

Body Size

1. Height & Weight

2. Surface area to mass ratio

Basal Metabolic Rate (BMR)

1. Breaks down energy

2. The minimum amount of energy (calories) required by the body to maintain essential functions while at rest

Diet

The food and drink a person or animal consumes

Resource Distribution

How a society distributes and shares everything it needs to survive and thrive

Predation

1. As predation pressure increases and resources decreases there will be smaller units

2. (Predation pressure ↑) + (Resources ↓) = Small Units

Dispersal

1. Who leaves the natal?

2. The movement of an individual primate away from the social group or area where they were born

Life Histories

Characteristics that affect a species’ reproductive rates

Strategies

Specific behaviors that increase individual or population reproductive success

Distribution and type of sleeping sites

Sleeping sites are a resource, Safety in any area

Activity Patterns

1. Diurnal: Active at day

2. Nocturnal: Active at night

Human Activites

Actions and behaviors from humans that influence and alter the natural behavior of NHP’s

Common Social Groups Among NHP’s (Rarest to Common)

1. One female, multimale

2. One male, one-female

3. Solitary

4. One-male-multifemale

5. Multimale-multifemale

One female, multimale

1. “Polyandrous”

2. Males help rear offspring

One male, one-female

1. Often called “pair bonding”

2. Mated pair and their young

Solitary

1. “dispersed polygyny”

2. Individuals who forage for food alone

3. Most nocturnal primates and orangutans

One-male-multifemale

1. “Polygynous” harems

Multimale-multifemale

1. Largest of the primate groups

Why Be Social?

1. Predation

2. Feeding

3. Mating

4. Infant Care

5. Health

Predation

Benefits: Protection

Costs: Conspicous

Feeding

Benefits: Intergroup competition

Costs: Intragroup competition

Mating

Benefits: Excess, options

Costs: Competition, conflict

Infant Care

Benefits: Assistance, protection

Costs: Abuse, Infanticide

Health

Benefits: Grooming

Costs: Parasites

Dominance Hierarchies

Individuals within a group are ranked in relation to one another

Dominance Hierarchies Info

1. Establishes Order

2. Learned and Temporary status

3. Higher ranking individuals

   • Greater fitness

     • Temporary

     • Risks

       • Power, Attacks, Cortisol, Vigilante —> Die Younger

Autonomic Responses

Involuntary physiological response to external stimuli, Body reacts and Innate

Voluntary Responses

Gestures, facial expressions, and vocalizations, which are intended forms of communication

Displays (aka “ritual displays)

1. A combination of behaviors meant to communicate emotional state

2. Often associated w/ “aggressive” behavior

3. Mean to avoid the cost of physical violence

4. Show aggressiveness w/out violence

Affiliative Behavior

1. Behaviors that create social cohesion between individuals and groups

2. Touching, handholding, hugging, and grooming

Grooming (aka “allogrooming)

1. Grooming among individuals of the same species

2. Adaptive function: hygiene and social bonding

3. Reciprocal, Homeostasis, Stability

Main Ideas

• anthropologists study primates to establish hypotheses and models about hominin evolution

• behavioral ecology is the study of behaviors and interactions between individuals within a

population from an evolutionary perspective

• behaviors, like any phenotype, can increase an individual's fitness and be selected for or against.

• social structures are the result of natural selection in a certain habitat

• many factors influence the composition and size of social groups among primates

• changes to the environment or habitat will affect social organization

• researchers commonly observe five types of primate social groups

• social groups increase the relative fitness of its individual members.

• there are many costs and benefits of living socially, but the benefits often outweigh the costs

• primates exhibit different social behaviors that increase the reproductive success of individuals within social groups