ANTH102 Study Guide - Exam #2
CHAPTER 4: PRIMATE BEHAVIOR
1. Primates as models for early human behavior
- Reconstructing behavior in fossil groups involves:
o Observing behaviors and social interactions in living species
o Ancient habitat reconstruction
o Noticing sexual dimorphism in fossil & extant (living) populations
Studying Primate Behavior
- Apes in the wild
o Difficult to gain confidence/trust of primates
o Difficult to track/find the primates
o But better able to judge behavior without human interference
- Apes in captivity (zoos, reserves, refuges)
o Convenient and easy to study
o But behavior is probably altered (stress)
2. The Primate Analogy
- “Because we cannot observe the way in which our ancestors behaved, and apes are our
closest living relatives, paleoanthropologists have been hopeful that living apes will shed
light on lifeways of our ancient pre-human ancestors/fossil species”
- Three primates are favored as models for how our ancestors may have behaved:
o Baboons
o Chimpanzees
o Bonobos
- Note: Goodall, Fossey, and Galdikas studied chimpanzees, gorillas, and orangutans… but
these apes are forest-dwellers (forests being environments that differ from grassy savannas
inhabited by the earliest human ancestors), so we turn to baboons that are native to
savanna habitats in Africa!
Baboons
- Old world monkeys native to savannas of Southern & Eastern Africa
- Advantages:
o Live in same environment as our ancestors
o There’s a lot of them
o High sexual dimorphism = aggression and male dominance in society, which was seen
as the norm in human evolution
- Problems:
o Not hominoids, so less closely related to us
Notice “ischial callosities” (hard butt pads) & tails
o Humans are less sexually dimorphic and not all human societies are organized around
dominance hierarchies (ranking system in which some animals outrank and
dominate others based on size and strength and other factors)
, Chimpanzees & Bonobos
- Advantages
o Share 98.5% of genetic material with humans
o Have capacity for cultural behavior (language and tool making)
o Chimps have an aggressive streak we assume was part of human evolution
o Bonobos are more like humans in terms of sexual behavior
No “estrus” (visible ovulation in females)
Receptive at all times
- Problems:
o They’ve undergone highly specialized adaptations
Knuckle-walking
o Humans have also changed significantly since 6mya
o We aren’t sure how they and humans are evolutionarily related
3. Behavioral Ecology
- Evolutionary basis for animal behavior due to environmental pressures
- Biology + Environment = Behavior
- Genotype + Environment = Phenotype
- Note: Biologists assume forces of natural selection work on behavioral traits just as
they do on genetic traits (example: cooperative behaviors and altruism/concern for
welfare of group and vocalizing a warning therefore making yourself a target to help the
group when a predator is around)
4. Behavioral Phenotypes
- Individuals whose behavioral phenotypes increase reproductive fitness pass on their genes
at a faster rate
5. Primate Social Structure
- Primates are among the most social of animals (live in groups)
- Video: Rhesus Monkey Society
o Monkeys that find food should announce or they will get attacked
- All primate societies are organized around dominance hierarchies
o Impose order by establishing parameters of individual behavior
o Higher-ranked have greater access to preferred food and partners
- Factors influencing status in groups are learned early!
o Age
o Sex
o Aggression
o Intelligence
o Mom’s social position (baboons)
o Predation and protection
- Each group /population of a species has a preferred social structure
o Orangutans = solitary
o Gibbons = monogamous
o Baboons = polygynous (one male, many females and babies)
o New world species = polyandrous (one female, many males and babies)
o Gorillas & Chimpanzees & Bonobos = multi-male multi-female
Gorillas are led by mature silverback male
, - Moms & infants are the basic social unit among all primates and are their relationship is
often maintained throughout life
6. Tool-making
- A tool is an object used to facilitate a task/activity
- Tool making involves intentional modifications
- The four large apes and some old world monkeys are able to make tools
- Ability to invent tools and to share the skill with others makes tool making a cultural
behavior (learned and shared and attached to a specific group)
o DIY Orangutans
o Sticks to judge depth of river
o “Imo”, a female macaque, washed sweet potatoes in salt water and got grains of
sand and grains of rice to spate in water and other individuals copied her
7. Hunting
- Many primates are omnivores and supplement their diet with meat
- Chimpanzees use teamwork to trap and brutally kill their food (red colobus monkeys and
babies)
- Bonobo females are the predominate hunters
8. Communication
- Human Communication
o Symbols
o Syntax
o Not dependent on direct stimulus
o Can be modified (new words and rules)
- Primate Communication
o Vocalizations/calls often used with face or body movement
Warning calls
Threat calls
Defense calls
Gathering calls
o Among bonobos, chimps, and gorillas, most vocalizations communicate an
emotional state, not information
o Orangutans shake branches to announce scary snake and fear/frustration
o Reassurance is communicated via hugs, kisses, hand holding, grooming
o Grooming = universal among all primates
o Captive apes can be taught to use symbols and follow syntax & modify the
language/create new words
Kanzi the bonobo uses lexigrams
Koko the gorilla uses American Sign Language (Assignment #2)
o Wild apes don’t use symbols or syntax and language is stimulus-dependent
o Displays
Threaten get big, get loud, show teeth
Sexual color, swelling, smell
CHAPTER 4: PRIMATE BEHAVIOR
1. Primates as models for early human behavior
- Reconstructing behavior in fossil groups involves:
o Observing behaviors and social interactions in living species
o Ancient habitat reconstruction
o Noticing sexual dimorphism in fossil & extant (living) populations
Studying Primate Behavior
- Apes in the wild
o Difficult to gain confidence/trust of primates
o Difficult to track/find the primates
o But better able to judge behavior without human interference
- Apes in captivity (zoos, reserves, refuges)
o Convenient and easy to study
o But behavior is probably altered (stress)
2. The Primate Analogy
- “Because we cannot observe the way in which our ancestors behaved, and apes are our
closest living relatives, paleoanthropologists have been hopeful that living apes will shed
light on lifeways of our ancient pre-human ancestors/fossil species”
- Three primates are favored as models for how our ancestors may have behaved:
o Baboons
o Chimpanzees
o Bonobos
- Note: Goodall, Fossey, and Galdikas studied chimpanzees, gorillas, and orangutans… but
these apes are forest-dwellers (forests being environments that differ from grassy savannas
inhabited by the earliest human ancestors), so we turn to baboons that are native to
savanna habitats in Africa!
Baboons
- Old world monkeys native to savannas of Southern & Eastern Africa
- Advantages:
o Live in same environment as our ancestors
o There’s a lot of them
o High sexual dimorphism = aggression and male dominance in society, which was seen
as the norm in human evolution
- Problems:
o Not hominoids, so less closely related to us
Notice “ischial callosities” (hard butt pads) & tails
o Humans are less sexually dimorphic and not all human societies are organized around
dominance hierarchies (ranking system in which some animals outrank and
dominate others based on size and strength and other factors)
, Chimpanzees & Bonobos
- Advantages
o Share 98.5% of genetic material with humans
o Have capacity for cultural behavior (language and tool making)
o Chimps have an aggressive streak we assume was part of human evolution
o Bonobos are more like humans in terms of sexual behavior
No “estrus” (visible ovulation in females)
Receptive at all times
- Problems:
o They’ve undergone highly specialized adaptations
Knuckle-walking
o Humans have also changed significantly since 6mya
o We aren’t sure how they and humans are evolutionarily related
3. Behavioral Ecology
- Evolutionary basis for animal behavior due to environmental pressures
- Biology + Environment = Behavior
- Genotype + Environment = Phenotype
- Note: Biologists assume forces of natural selection work on behavioral traits just as
they do on genetic traits (example: cooperative behaviors and altruism/concern for
welfare of group and vocalizing a warning therefore making yourself a target to help the
group when a predator is around)
4. Behavioral Phenotypes
- Individuals whose behavioral phenotypes increase reproductive fitness pass on their genes
at a faster rate
5. Primate Social Structure
- Primates are among the most social of animals (live in groups)
- Video: Rhesus Monkey Society
o Monkeys that find food should announce or they will get attacked
- All primate societies are organized around dominance hierarchies
o Impose order by establishing parameters of individual behavior
o Higher-ranked have greater access to preferred food and partners
- Factors influencing status in groups are learned early!
o Age
o Sex
o Aggression
o Intelligence
o Mom’s social position (baboons)
o Predation and protection
- Each group /population of a species has a preferred social structure
o Orangutans = solitary
o Gibbons = monogamous
o Baboons = polygynous (one male, many females and babies)
o New world species = polyandrous (one female, many males and babies)
o Gorillas & Chimpanzees & Bonobos = multi-male multi-female
Gorillas are led by mature silverback male
, - Moms & infants are the basic social unit among all primates and are their relationship is
often maintained throughout life
6. Tool-making
- A tool is an object used to facilitate a task/activity
- Tool making involves intentional modifications
- The four large apes and some old world monkeys are able to make tools
- Ability to invent tools and to share the skill with others makes tool making a cultural
behavior (learned and shared and attached to a specific group)
o DIY Orangutans
o Sticks to judge depth of river
o “Imo”, a female macaque, washed sweet potatoes in salt water and got grains of
sand and grains of rice to spate in water and other individuals copied her
7. Hunting
- Many primates are omnivores and supplement their diet with meat
- Chimpanzees use teamwork to trap and brutally kill their food (red colobus monkeys and
babies)
- Bonobo females are the predominate hunters
8. Communication
- Human Communication
o Symbols
o Syntax
o Not dependent on direct stimulus
o Can be modified (new words and rules)
- Primate Communication
o Vocalizations/calls often used with face or body movement
Warning calls
Threat calls
Defense calls
Gathering calls
o Among bonobos, chimps, and gorillas, most vocalizations communicate an
emotional state, not information
o Orangutans shake branches to announce scary snake and fear/frustration
o Reassurance is communicated via hugs, kisses, hand holding, grooming
o Grooming = universal among all primates
o Captive apes can be taught to use symbols and follow syntax & modify the
language/create new words
Kanzi the bonobo uses lexigrams
Koko the gorilla uses American Sign Language (Assignment #2)
o Wild apes don’t use symbols or syntax and language is stimulus-dependent
o Displays
Threaten get big, get loud, show teeth
Sexual color, swelling, smell
