Re: Social evolution of hominids

Peter Crowley (
Sat, 11 Jan 1997 01:05:29 GMT (Susan S. Chin) wrote:

> wrote:

>: . 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?

In a chimp band only a few of the females will be in estrus
at any one time. Often it will be none at all. But when
they are, they will go around in a large excitable group
with most of the males. In consequence chimps, especially
males, develop gang behaviour. So continuous female
receptivity would destroy the basis of chimp society.

>: 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?
No *direct* effect on "child care" since the females do all
the work in any case. But you're missing the effect on the
dynamics of the group. The main achievement of chimpanzees
was the establishment of the multi-male co-operative group.
This gave them dominance in the forest. Promiscuous sex.
was an essential factor. Also a male will protect all
infants in the group since each one could be his progeny.
When a group expands to more than about a dozen mature
males, this probability goes down, the whole system gets
difficult to manage, and the group becomes liable to split.
The introduction of either excessive pairing or continuous
receptivity would destroy the genetic and behavioural bases
of chimp co-operation. Each pair would probably set up its
own territory. But since neighbouring multi-male groups
would be much stronger, such chimps would not survive.

>I see no problem with disagreeing with Lovejoy's theory...many people in
>Anthropology have a hard time with it. His theory goes way beyond the
>loss of estrus in human females, the subsequent pair bonding as a result,
>explained by the advantage for hominid females to have one male providing
>for their offspring, this provisioning behavior...eventually led to
>bipedalism, as it required that the males free up the hands for carrying
>these provisions to the offspring.

Lovejoy's is a fairly desperate attempt at explaining
bipedalism, (but no worse than most ). Since chimps
achieved strong multi-male groups with female exogamy and we
are *in_effect* descended from them and we have multi-male
groups with female exogamy, its most unlikely that we ever
went through another phase. Monogamy has to be seen as one
aspect of the development of co-operative multi-male groups
with more than a dozen adult males.

> The way human ancestors
>differed from our closest living primate relatives, is in the expansion
>of our habitat beyond a forrested environment. This is one significant
>evolutionary change in behavior which likely had direct consequences on
>how our ancestors adapted...both morphologically and behaviorally.

Agreed. Survival in the open would require much better

>The degree of sexual dimorphism between a human male and a human female
>would at least suggest that differences in size between the sexes nowhere
>near approaches that of modern apes such as the orang and gorilla. What
>would this suggest to you?

We do not have many species of large, terrestrial primates
which operate in open spaces in highly co-operative
multi-male groups -- on which to form observational rules
regarding dimorphism. Or are you happy to extend rules
based on small aboreal primates living in the high canopy?

>: 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.

This is an absurd picture. What world are you living in?
Sex results in babies and females only provide it as part of
a highly developed survival and reproductive strategy. The
females of promiscuous species, such as chimps, provide it
because they want all the males to protect them and their
infants. Protection is also an important reason in
monogamous species such as gibbons. For hominids, I'd rate
protection by a group of (sexually contented) co-operating
males as being much more important than provisioning. The
male instinct to provide for his (probable) offspring seems
much weaker than the female's; and the male combative one
is remarkably strong. (How many females are keen sports

>There was never a claim in Lovejoy's Theory that humans have evolved to
>accept monogamy as a rule, since that has obviously not happened.

What? The vast bulk of humanity accepts monogamy as the
rule, and has done so throughout recorded history.

>social evolution has gone way way way beyond mere providing for our
>offspring by securing that next meal (it is hoped anyway)...but when the
>basics of life, death and food which your offspring needs... go figure
>what the response would be.

What do you mean by this? There are numerous recent
periods and locations when the "basics of life" got very
close to a lot of people. Are you saying that the social
and family structure normally broke down?

Apologies for mixing replies, but "ailak@walrus's" posting did not reach me.