( From “Mismatch: Why our World No Longer Fits our Bodies”, 2006
by Peter Gluckman and Mark Hanson )
…Within the primate family virtually every social possibility and arrangement exists. At one extreme, the orangutan is a solitary species – adults have their own home territories and males and females only associate to mate. Offspring are brought up by the female with little input from the male.
At the other extreme, baboons have adopted multi-male polygyny, living in large groups of adult males and females and their offspring. The males compete strongly for mating, and there is often a single dominant male, but they cooperate to defend their territory from other groups. Subdominant males may engage in ’sneaky’ mating.
Chimpanzees also live in multi-male, multi-female groups, but their social interactions are much more complex… There are diverse patterns of mating – for example, chimpanzee females may mate with several males, possibly as a strategy against infanticide by confusing paternity.
Some primate species, for example the gibbon, are monogamous, forming long-term pairs of an adult male and female with their offspring.
Conversely, some New World primates such as marmosets adopt polyandry, living in groups of a single adult female with her offspring together with several adult males with which she mates. In this situation, although the males cannot ‘know’ that the offspring are theirs, their best strategy is to support the female and offspring on the assumption that this is the case.
Finally, humans are generally monogamous, forming long-term pairs and with both parents having high investment in their children… Because the human life-course strategy is based on a single child per pregnancy, a long period of nurturing of the offspring and a reasonably stable pairing arrangement between parents who have joint investment in the offspring is ideal…
Humans are not at much risk from other species. But we have evolved in an environment in which threats from our own species are real. Warfare and intra-specific (human on human) violence remains a dominant issues in our survival, both as individuals and as a species. Sociobiologists who examine behaviour from an evolutionary perspective suggest that we have developed a range of group behaviours to reduce the threat of competition between members of a human group. It is suggested that this is in part the evolutionary origin of behaviour such as altruism and the development of our sense of moral and ethical standards… .
However, perusal of the more lurid Sunday newspapers will soon provide human examples of most of the strategies adopted by our fellow primates…