Summary after the break.
- female vervet monkeys know not just which babies are their own, but which babies belong to which other mothers
- ” ‘Monkey society is governed by the same two general rules that governed the behavior of women in so many 19th-century novels…. Stay loyal to your relatives (though perhaps at a distance, if they are an impediment), but also try to ingratiate yourself with the members of high-ranking families.’ Baboon society revolves around mother-daughter lines of descent. Eight or nine matrilines are in a troop, each with a rank order. This hierarchy can remain stable for generations. By contrast, the male hierarchy, which consists mostly of baboons born in other troops, is always changing as males fight among themselves and with new arrivals. Rank among female baboons is hereditary, with a daughter assuming her mother’s rank. “
- “On two occasions, baboons have attacked animals, a leopard and a honey badger, that threatened their human companions.”
“For female baboons, another constant worry besides predation is infanticide. Their babies are put in peril at each of the frequent upheavals in the male hierarchy. The reason is that new alpha males enjoy brief reigns, seven to eight months on average, and find at first that the droits de seigneur they had anticipated are distinctly unpromising. Most of the females are not sexually receptive because they are pregnant or nurturing unweaned children.
An unpleasant fact of baboon life is that the alpha male can make mothers re-enter their reproductive cycles, and boost his prospects of fatherhood, by killing their infants. The mothers can secure some protection for their babies by forming close bonds with other females and with male friends, particularly those who were alpha when their children were conceived and who may be the father. Still, more than half of all deaths among baby baboons are from infanticide.
So important are these social skills that it is females with the best social networks, not those most senior in the hierarchy, who leave the most offspring.”
- “In some of their playback experiments, Dr. Cheney and Dr. Seyfarth have tested baboons’ knowledge of where everyone stands in the hierarchy. In a typical interaction, a dominant baboon gives a threat grunt, and its inferior screams. From their library of recorded baboon sounds, the researchers can fabricate a sequence in which an inferior baboon’s threat grunt is followed by a superior’s scream. Baboons pay little attention when a normal interaction is played to them but show surprise when they hear the fabricated sequence implying their social world has been turned upside down.”
- “Baboons seem to have a very feeble theory of mind. When they cross from one island to another, ever fearful of crocodiles, the adults will often go first, leaving the juveniles fretting at the water’s edge. However much the young baboons call, their mothers never come back to help, as if unable to divine their children’s predicament.”
- “It is far from clear why humans acquired a strong theory of mind faculty and baboons did not. Another difference between the two species is brain size. Some biologists have suggested that the demands of social living were the evolutionary pressure that enhanced the size of the brain. But the largest brains occur in chimpanzees and humans, who live in smaller groups than baboons. But both chimps and humans use tools. Possibly social life drove the evolution of the primate brain to a certain point, and the stimulus of tool use then took over.”
- “Baboons provide you with an example of what sort of social and cognitive complexity is possible in the absence of language and a theory of mind…”