"Bonobo: The Forgotten Ape" by Frans De Waal and Frans Lanting

This is not only a book by one of today's leading primatologist but it is also a book is filled with beautiful pictures. The unusual thing about Bonobos is that they form matriarchial societies.

Bonobos are a great ape species that split from chimpanzees 3 million years ago (only recently discovered). Humans in turn split from the common Bonobo - Chimpanzee ancestor 6 million years ago. Humans specialized for savanna living while Chimpanzees specialized for mixed forest and savanna living while Bonobos specialized for pure forest living. These different specializations led to different group behaviors.

The forest provides all the protein the Bonobos need from just foraging. In contrast both chimpanzees and humans have to hunt to get enough protein on the savanna. This means males must do the hunting as the females are burdened with young ones. In addition the human - champanzee groups cannot climb trees when threatened on the savanah but instead must defend themselves, another male function. All this favors male bonding and the development of physical aggression which is then carried over into group dynamics. The result is male domination of the group.

These male characteristics never evolved (or were lost) in Bonobos because their environment did not require them. This leaves the Mother as the authority figure for all young Bonobos, and mothers are just not attackable. Even grown male Bonobos will follow their mothers around in the forest. This motherly authority and lack of male bonding resulted in female cooperation for group decisions.

In both Bonobo and Chimpanzee society the males stay with their birth group leaving the females stray out to other groups in order to prevent inbreeding. This pattern seems to be the dominant cultural pattern in most ancient human cultures as well.

The evolutionary drive for male bonding in Chimpanzees is that cooperation will allow a small group of males to dominate the group and thus have better access to females at mating time. In contrast, the drive for female bonding in Bonobos seems to be the cooperation to get food without injury to each other. The only behavior as strong as the urge to eat is sex. As a result Bonobo society is built around sex of all kinds all the time with female - female sex being a prevelent as male - female sex. In general sex is a general reducer of social tension within Bonobo society. If food is tossed between two females they will have some sex before both approach the food which they then proceed to share. The males are forced to wait until they are done.

Males still have a ranking order in Bonobo society that gives higher ranking males greater odds of producing offspring but that ranking parallels that of their mothers. Yet exact paternity cannot be known by the males. One result of this seems to be the lack of infanticide when a new set of dominant males takes over the group. This infanticide is common and ranges from "lions to prairie dogs, and from mice to gorillas" (page 118). Infanticide as a proportion of all infant mortality in Mountain Gorillas is 37% (page 118). The advantage of infanticide to the male is that females without young will be willing to mate with the new dominant male or males much sooner.