Bonobos, Chimps, Fatherhood, and the Origins of Human Society

I've been reading Bonobo: the Forgotten Ape, a large format book with text by primatologist Frans de Waal and amazing photographs by Frans Lanting (1997). It's a fascinating book, full of information but highly readable, and I recommend it.

What started me thinking hard was some speculation de Waal throws out about the origins of human society. Compared to chimps and bonobos, the immediately striking thing about primitive human cultures is the centrality of the family. Hunter-gatherers have at least three different kinds of strong bonds: male-male bonds, female-female bonds, and the family made up of mother, father, and offspring. Chimps and bonobos have the first two but they have no families. So far as we can tell, neither chimps nor bonobos have any idea who the father of an infant is. Among both species mothers of young offspring tend to be suspicious of males. This is especially so among chimps, where new mothers separate themselves from the group and live largely alone because of fear that a male might kill their babies. Among bonobos infanticide has not yet been observed, but mothers are still careful around males and they stick to the center of a group of females, keeping males away on the edges.

De Waal thinks that once humans began living on the savanna, mothers could no longer support themselves and their offspring without male help. They therefore needed the father to hang around and provide support. The father would only do this if he was fairly sure the baby was his. Thus, de Waal speculates, one of the key events in human evolution is the recognition of paternity, and this in turn is the root of the "homicidal jealousy" of the human male. Since chimp and bonobo fathers make no investment in their offspring, the promiscuity of their mates is of small concern to them. But for human males, the key evolutionary fact is that they can increase the survival of their offspring by investing heavily in their upbringing. And they generally do, but only if they have good reason to believe that the babies are really theirs. Seen this way, many things about human tribal societies make much more sense.