http://soong.club.cc.cmu.edu/~julie/bonobos.html

Bonobo Sex and Society

           The behavior of a close relative challenges assumptions
                  about male supremacy in human evolution

                                     by

                             Frans B. M. de Waal

     [(Originally published: March 1995 SCIENTIFIC AMERICAN, pp. 82-88)]


At a juncture in history during which women are seeking equality with
men, science arrives with a belated gift to the feminist movement.
Male-biased evolutionary scenarios-- Man the Hunter, Man the Toolmaker
and so on--are being challenged by the discovery that females play a
central, perhaps even dominant, role in the social life of one of our
nearest relatives. In the past few years many strands of knowledge have
come together concerning a relatively unknown ape with an unorthodox
repertoire of behavior: the bonobo.

The bonobo is one of the last large mammals to be found by science. The
creature was discovered in 1929 in a Belgian colonial museum, far from
its lush African habitat. A German anatomist, Ernst Schwarz, was
scrutinizing a skull that had been ascribed to a juvenile chimpanzee
because of its small size, when he realized that it belonged to an adult.
Schwarz declared that he had stumbled on a new subspecies of chimpanzee.
But soon the animal was assigned the status of an entirely distinct
species within the same genus as the chimpanzee, Pan.

The bonobo was officially classified as Pan paniscus, or the diminutive
Pan. But I believe a different label might have been selected had the
discoverers known then what we know now. The old taxonomic name of the
chimpanzee, P. satyrus-- which refers to the myth of apes as lustful
satyrs--would have been perfect for the bonobo.

The species is best characterized as female-centered and egalitarian and
as one that substitutes sex for aggression. Whereas in most other species
sexual behavior is a fairly distinct category, in the bonobo it is part
and parcel of social relations--and not just between males and females.
Bonobos engage in sex in virtually every partner combination (although
such contact among close family members may be suppressed). And sexual
interactions occur more often among bonobos than among other primates.
Despite the frequency of sex, the bonobo's rate of reproduction in the
wild is about the same as that of the chimpanzee. A female gives birth to
a single infant at intervals of between five and six years. So bonobos
share at least one very important characteristic with our own species,
namely, a partial separation between sex and reproduction.

                              A Near Relative

This finding commands attention because the bonobo shares more than 98
percent of our genetic profile, making it as close to a human as, say, a
fox is to a dog. The split between the human line of ancestry and the
line of the chimpanzee and the bonobo is believed to have occurred a mere
eight million years ago. The subsequent divergence of the chimpanzee and
the bonobo lines came much later, perhaps prompted by the chimpanzee's
need to adapt to relatively open, dry habitats [see "East Side Story: The
Origin of Humankind," by Yves Coppens; SCIENTIFIC AMERICAN, May 1994].

In contrast, bonobos probably never left the protection of the trees.
Their present range lies in humid forests south of the Zaire River, where
perhaps fewer than 10,000 bonobos survive. (Given the species' slow rate
of reproduction, the rapid destruction of its tropical habitat and the
political instability of central Africa, there is reason for much concern
about its future.)

If this evolutionary scenario of ecological continuity is true, the
bonobo may have undergone less transformation than either humans or
chimpanzees. It could most closely resemble the common ancestor of all
three modern species. Indeed, in the 1930s Harold J. Coolidge--the
American anatomist who gave the bonobo its eventual taxonomic
status--suggested that the animal might be most similar to the
primogenitor, since its anatomy is less specialized than is the
chimpanzee's. Bonobo body proportions have been compared with those of
the australopithecines, a form of prehuman. When the apes stand or walk
upright, they look as if they stepped straight out of an artist's
impression of early hominids.

Not too long ago the savanna baboon was regarded as the best living model
of the human ancestor. That primate is adapted to the kinds of ecological
conditions that prehumans may have faced after descending from the trees.
But in the late 1970s, chimpanzees, which are much more closely related
to humans, became the model of choice. Traits that are observed in
chimpanzees--including cooperative hunting, food sharing, tool use, power
politics and primitive warfare--were absent or not as developed in
baboons. In the laboratory the apes have been able to learn sign language
and to recognize themselves in a mirror, a sign of self-awareness not yet
demonstrated in monkeys.

Although selecting the chimpanzee as the touchstone of hominid evolution
represented a great improvement, at least one aspect of the former model
did not need to be revised: male superiority remained the natural state
of affairs. In both baboons and chimpanzees, males are conspicuously
dominant over females; they reign supremely and often brutally. It is
highly unusual for a fully grown male chimpanzee to be dominated by any
female.

Enter the bonobo. Despite their common name -- the pygmy chimpanzee --
bonobos cannot be distinguished from the chimpanzee by size. Adult males
of the smallest subspecies of chimpanzee weigh some 43 kilograms (95
pounds) and females 33 kilograms (73 pounds), about the same as bonobos.
Although female bonobos are much smaller than the males, they seem to
rule.

[continued]

	to read the rest of this fascinating article, which appeared in
the m2m(#19?), set your sights to:

http://soong.club.cc.cmu.edu/~julie/bonobos.html


	of course, i'll mail anyone the full article who doesn't have web
access.  just let me know.


learning,
	 bodhi