Re: Social evolution of hominids
8 Jan 1997 01:38:31 +0200 wrote:

> The loss of estrus, the period of sexual receptivity in non-human prim
> lead to continuous sexual activity in human females, who were now with
> obvious "signs" of female fertility. The benefit of continuous sexual
> receptivity in human females, according to Owen Lovejoy, is to ensure
> that the male stays with the female, even during periods when she's no
> fertile (ovulating). This was accomplished by hidden estrus, since
> fertility is not evident...sexual activity is continuous. Well, that i
> his theory anyway.

I am nobody to disagree with an anthro prof, but I feel uncomfortable
with this theory. In which way would continuous receptivity (or
anything else) make the male stay with the female better than a
chimp male stays with a female in their permanent group? What would
be the difference in child care if the males and females of a chimp
group were permanently paired instead of having the way they do?

The orang has a social system with dominant males in their revirs and
the females and younger males wandering around. They are more
solitary than the African species. What would happen, if the orang
females became continuously receptive. Wouldn't *they* hang with the
males in the revirs, since the females prefer these big males? That
would lead to a system of sedentary pairs, or harems, if there were
continuously more males than available revirs?

The gorilla lives in groups with steep male hierarchy. If the gorilla
females turned continuously active, the big top gorilla would have
really hard times! He'd have to handle the whole bunch of eager
females, and fight with other males all time. The hierarchy should
become less steep, and quick, for the group to survive. But that
would lead to promiscuity, without additional modifications to create
pair bonds. The top male achieves his priority by fighting with the
other males, not by creating pair bonds with the females.

I believe that something like has happened in the chimp line.
Male chimps are less hierarchic and bonobo females are continuously
receptive with promiscuous sex. This does not tell which trait came
first, but we know that such solution does exist in the ape line.
Tight pairs, instead, do not appear before Homo s., if not some
monkeys have such organization?

If the bonobo strategy was chosen by the pre-hominids millions of
years ago is another thing, but then there are the !kung san.
That means, that this strategy does exist in the hominid line, too,
and the position of the !kung san in our species excites imagination.
There are relatively loose pair bonds in other primitive (and less
primitive :) cultures, where women earn considerable portions of
the living, and relatively free sex in south of Saharan African
cultures in general. Male polygamy is common throughout the human
kind, but women don't resist female polygamy where it occurs.
And a woman with a man and a lover is polygamous? Or promiscuous?

The whole pair system of humans seems to me new and learned.
Such deep, instinctive devotion to the selected mate which could be
expected if this was a very old trait, and which is present in many
birds, does occur for short periods only, in the beginning of pair
life. After that, the pair is bound together mainly by social
pressure, or economy, or decision, or good company, but the
instinctive feeling of 'falling in love' seldom stays longer than
two three years, if even that. Even jealousness is not a definitely
sex-linked sensation.

Lorenz's rooks and geese got paired for lifetime. They, too, live
in groups but need not care for their young for years. The alpha
female wolf has fought her way to the top and the alpha male accepts
what is available, and vice versa. They make a permanent pair as
far as they stay in command, but mate once a year. These tight pair
bonds have nothing to do with permanent sex.

I find it difficult to imagine, how the mere hanging around of a
certain man would specially enhance the care of the children. Since
the number of men and women is equal, there would always be a man
hanging around, anyway. And since other women are receptive, too,
continuous sex would be available for him anywhere.

I can think that permanent pairing would cool down continuous
competing for sex partners between men as well as women, and direct
the energy to other survival questions. It would lead to *less*
sexual activity, instead of luring the man with *more* sex. This, in
turn, could enhance the care of the children. I believe, that the
continuous receptivity of women had nothing to do with pairing. In
fact, the latter could be a step back to restricted mating times.
Any observations? ;)

> Susan
> --

Aila Korhonen in Finland