Anthropology Chapter 3

Slides: Primate Habitats and sociality

Studying behavior

-Proximate — How did it develop

-Ultimate — Why did it evolve

Mating Systems

Monogamy - Breeding (1 male:1 female)

Polygyny - Breeding (1 male: multifemale)

Polyandry - Breeding (multimale: 1 female)

Polygyandry - Breeding (multimale: multifemale)

Social Systems

Solitary/semi-solitary

One male units

Multimale/multifemale group

One female, multimale units

Fission-fussion groups - Groups always changing in size and composition

Fission-fussion determinants

-Resources

-Leadership ability

-Species density

-Predation risks

Who takes care of babies

-Mostly mothers

-Sometimes males significantly help

-Sometimes other females

Who’s in charge

-Alpha males

-Alpha/mother female

*Baboon Social Rank

*Marmosets and tamarins

-Both/unknown

Foraging Theories

-Optimal foraging theory and Marginal Value Theorem

-Geometric Framework of Nutrition

Optimal Foraging Theory

• Maximizing intake of energy or nutrient/time
• Energy or nutrient = currency
• Other needs = constraint

• Useful and testable

Optimal Foraging Theory Criticisms

• Too simplistic

• Dynamic nature of food and nutrient interactions unaccounted for

• Constraints are not viewed as critical parts of model

Optimal Foraging Theory: Marginal Value Theorem

• “The predator should leave a patch it is presently in when the marginal capture rate in
the patch drops to the average capture rate for the habitat.” (Charnov 1976 p. 132)
• “An important assumption of the model is that while the predator is in a patch, its food
intake rate for that patch decreases with time spent there.” (Charnov 1976 p. 129)

MVT is not supported in…

• Meta-analysis

• Orangutans

• Gibbons

Geometric Framework of Nutrition

Capital vs. Income Breeders

-Organisms that build up
energy reserves prior to
breeding, then reproduce

-Organisms that rely on
energy intake during
breeding season for
reproduction