Who lives with who (residence patterns)
The most common type of primate social group: one male living with several females and their young.
A. One-male, one-female (monogamy)
B. One-male, multifemale (polygyny)
C. One-female, multimale (polyandry)
A female primate's reproductive success is limited mainly by access to this, while a male's is limited by access to females.
A. Mates
B. Food and other resources
C. Allies
What are "food and other resources"?
Vervet monkeys give different calls for leopards, eagles, and snakes. A recording alone makes listeners climb trees, look up, or scan the ground. These signals are called this.
A. Contact calls
B. Alarm calls
C. Food calls
When one primate combs through another's fur, removing dirt, dead skin, and parasites, the behavior is called this.
A. Allogrooming
B. Autogrooming
C. Display
Care of an infant by group members other than its mother, seen in langurs and other groups where related females live together, is called this.
A. Weaning
B. Allomothering
C. Imprinting
What is "allomothering"?
These small Southeast Asian apes, along with their larger relatives the siamangs, are the textbook example of one-male, one-female living (monogomy).
A. Orangutans
B. Bonobos
C. Gibbons
What are "Gibbons"?
Primates that rely on scarce, scattered foods such as insects are most likely to live this way.
A. Solitary
B. In multimale, multifemale troops
C. In one-male, multifemale groups
What are "solitary" residential patterns?
Two or more primates teaming up against a third, as when older male olive baboons join forces to take a mating partner from a higher-ranking rival.
A. Coalition
B. Dominance hierarchy
C. Group action
What is a "coalition"?
No primate species spends more than about this share of its day on social grooming, which limits how large a grooming-bonded group can grow.
A. About 5%
B. About 20%
C. About 50%
What is "about 20%"?
In Harry Harlow's experiments, infant rhesus monkeys clung to a soft cloth "mother" and visited a wire "mother" only to feed from its bottle. This showed the importance of this.
A. Contact comfort
B. Imprinting
C. Food reward
What is "contact comfort"?
Common chimpanzees live in large multimale, multifemale communities that split into small foraging parties and later rejoin. This flexible arrangement is called this.
A. Noyau
B. Fission-fusion
C. Bachelor group
What is "Fission-Fusion"?
In some Tibetan and Himalayan communities, one woman marries a set of brothers, who share economic and household responsibilities. This system is called this.
A. Polygyny
B. Fraternal polyandry
C. Serial monogamy
What is "fraternal polyandry"?
Chimpanzees in Taï Forest, Côte d'Ivoire, hunt red colobus monkeys by taking roles such as drivers, blockers, and ambushers. Hunters who play the key roles are rewarded with this.
A. The largest share of the meat
B. Grooming from the alpha male
C. First access to mates
What is "the largest share of meat"?
Some chimpanzee communities raise clasped hands overhead while grooming, while neighboring communities never do, or clasp wrists instead of palms. Researchers read this as evidence of this.
A. Genetic differences between groups
B. Differences in parasite load
C. Social tradition
What is "social tradition"? (i.e. culture)
Genetic tests showed this pair-living South American monkey is truly monogamous, and its fathers carry infants about 80–90% of the time after the first few weeks.
A. Howler monkey
B. Spider monkey
C. Owl (night) monkey
What is an "owl monkey"?
In this solitary system, seen in orangutans and some prosimians, one male's range covers the ranges of several females, and individuals come together mainly to mate.
A. Noyau
B. Fission-fusion
C. Communal breeding
What is "Noyau"?
Males from an all-male "bachelor" group may evict the resident male of a one-male group and then kill unweaned infants. This behavior is called this.
A. Infanticide
B. Allomothering
C. Reconciliation
What is "infanticide"?
Capuchin monkeys trading tokens for cucumber slices often refused once a partner received grapes for the same work. Researchers called this reaction this.
A. Reciprocal altruism
B. Inequity aversion
C. Kin selection
What is "inequity aversion"?
A 16-year study of wild baboons in Amboseli, Kenya, found that females with the strongest social bonds had higher rates of this.
A. Infant survival
B. Dominance rank
C. Number of mates
What is "infant survival"?
Chemical traces in teeth show that mothers of this ape can nurse offspring for more than 8 years, the longest of any wild mammal.
A. Orangutan
B. Gorilla
C. Chimpanzee
What is an "orangutang"?
One-female, multimale groups are the rarest primate social system and occur only in this family of small New World monkeys.
A. gibbons and siamangs
B. chimpanzees and gorillas
C. marmosets and tamarins
What are "marmosets and tamarins"?
Many mammals detect pheromones with this structure, but it appears poorly developed in humans, one reason human pheromones remain debated.
A. Olfactory bulb
B. Apocrine gland
C. Vomeronasal organ
What is a "vomeronasal organ"?
In standardized helping experiments across 15 primate species, including humans, this trait was by far the best predictor of spontaneously helping others.
A. Brain size
B. Group size
C. Allomaternal care
What is "allomaternal care"?
Wild chimpanzees in Uganda's Budongo Forest had higher levels of this hormone after grooming with a close "bond partner," whether or not the partner was a relative.
A. Cortisol
B. Testosterone
C. Oxytocin
What is "Oxytocin"?
Humans have the longest childhood of any primate, yet compared with other great apes, mothers in natural-fertility societies do this, largely thanks to help from fathers, grandmothers, and older siblings.
A. Nurse each infant longer
B. Raise only one dependent child at a time
C. Give birth at shorter intervals