Longish, this is the link for the printer version

http://www.nytimes.com/2003/11/25/sc...rint&position=

Fossil bones record the history of the human form but they say little about
behavior. A richer source on the way human social behavior evolved may come
from chimpanzees, with whom people shared a common ancestor as recently as
five or six million years ago.

From knowledge of chimp behavior, biologists can plausibly infer the social
behavior of the shared human-chimp ancestor, and from that reconstruct the
evolutionary history of human social behavior.

Such reconstructions are subject to much uncertainty and debate, especially when
they imply a genetic basis to human behaviors like living in communities based
on male kinship, or conducting lethal campaigns against neighbors. But the goal
is to shed light on the full sweep of human social behavior, tracing its evolution
from an apelike community with separate male and female hierarchies five million
years ago to the family-based societies of today.

A principal assumption is that chimpanzees, unlike people, have changed little and
therefore their social behavior is a good guide to that of the common ancestor.
One support for this idea is that the earliest fossils on the human side after the
split are very chimplike. Another is that the chimps of western and eastern Africa
are hard to tell apart, despite some 1.5 million of years of separate evolution.

After 40 years of arduous study, biologists have put together a coherent, if not yet
complete, picture of chimpanzee societies. [...]
[...]
A major surprise has been that chimps turn out to live in territories whose borders
are aggressively defended by roving parties of males. Jane Goodall, who pioneered
long-term studies of chimps at Gombe, at first believed she was watching a single
peaceful community. But as researchers started to follow animals throughout the
day and watch their interaction with others, they found that groups of male chimps
went out on border patrols, ready to attack and kill the males of neighboring
communities.

The males in each community are related to one another because they spend their
lives
where they were born, whereas the females usually migrate to neighboring communities
soon after reaching puberty, a practice that avoids inbreeding. This patrilocal
system,
of a community based on male kin bonding, is unusual, but familiar to
anthropologists
because it is practiced by most hunter-gatherer societies.

The males' operational strategy seems to be to defend a territory as large as
possible
so as to improve the community's food supply, which is principally fruit, and
thereby
their reproductive success. Dr. Anne Pusey of the University of Minnesota has found
that the larger the female chimp's home feeding area, the shorter the interval
between
births.
[...]
Within a community, there is a male hierarchy that is subject to what primatologists
euphemistically call elections. Alpha males can lose elections when other males form
alliances against them. Losing an election is a bad idea. The deposed male sometimes
ends up with personal pieces torn off him and is left to die of his wounds.

Very few other species live in male-kin-bonded communities with female dispersal.
And
only two practice lethal raids into neighbors' territory to kill off vulnerable
enemies. "This suite of behaviors in known only among chimpanzees and humans," Dr.
Wrangham and Dale Peterson write in their book "Demonic Males."
[...]
Males and females do not associate in families but in separate hierarchies. Males
make
females defer to them, with violence whenever necessary, and every female is
subordinate to every male. A female chimp advertises her fertile period with a
visible
swelling and is then so pestered by males that she may get to eat only at night. But
the great advantage of mating with every male in the community in a public orgy is
that
it confuses paternity, significant insurance given that males are liable to kill
infants they know are not their own.
[...]
An intriguing variation on the chimpanzee social system is that of bonobos, which
split
from chimps some 1.8 million years ago. With bonobos, who live in Congo south of the
Congo River, the female hierarchy is dominant to that of males, and males do not
patrol
the borders to kill neighbors. Though bonobos are almost as aggressive as chimps,
they
have developed a potent reconciliation technique — the use of sex on any and all
occasions, between all ages and sexes, to abate tension and make nice.

Assuming the common ancestor of people and chimps had social behavior that was
essentially chimplike, how much of that behavior has been inherited by people? The
unusual behavioral suite of male kin bonding and lethal territorial aggression may
look
as if it has been inherited with little change. Among the Yanomamo, a South American
tribe, the number of males who die from aggression is about 30 percent, the
identical
rate found among Gombe chimps.

Dr. Wrangham said the consistent pattern of aggression seen at all the chimp sites
suggests that male chimps have "a strong emotional disposition" to be aroused by the
sight of strange males, to form coalitions against enemies, to be sensitive to
balances
of power and to be attracted to hunting. The same disposition could have been
inherited
down the human lineage.
[...]
Not everyone believes that chimp social behavior is a good guide to human evolution.
"All these things are suggestive and point tantalizingly to things we want to know,"
said Dr. Ian Tattersall, a paleoanthropologist at the American Museum of Natural
History.
"We just have to bear in mind that none of this is demonstrable in any highly
convincing
way."

But Dr. Robert Foley, an evolutionary anthropologist at the University of Cambridge
in
England, thinks a lot can be learned from ape sociality about the evolution of
human
social institutions. A community size of 80 to 100 people, typical among chimps and
hunter-gatherers, is one feature inherited from the common ancestor. Another is a
society formed on the basis of male kin bonding. "Out of that flows the notion of
the way
males relate to each other, they way they form alliances, the levels of
cooperation," he
said.
[...]
A critical event in human social evolution must have been the transition from the
male
and female hierarchies of chimp society to the conjugal bonds between men and women.
Both Dr. Wrangham and Dr. Foley believe the new mating system is likely to have
occurred
about 1.9 million years ago with the evolution of Homo erectus. The size difference
between the sexes shrank sharply at that time. Dr. Wrangham sees the invention of
cooking, which opened up a wide new range of more nutritional foods, as the spur to
the females' larger size. Dr. Foley favors meat eating, which helped mothers bear
children with larger brains.

The two explanations, which are not incompatible, both envisage human institutions
as
adapting to some important improvement in available resources. The upshot would have
been that men found they attained greater reproductive success by spending more time
with
the mother of their children. The larger-brained offspring would have been harder to
raise. That required a more dependable food supply, leading to a "much tighter bond
between males and females," Dr. Foley said.

The movement away from the male hierarchy evidently continued to evolve because
hunter-gatherer societies, in which modern humans have spent four-fifths of their
existence, are notably egalitarian, with not an alpha male in sight. Then, with the
first sedentary societies and the rise of agriculture some 10,000 years ago, the
first
signs of social ranking appear in the archaeological record, followed by the
chieftains,
priests, property rules and the coercive authority of modern states.
...

On Tue, 25 Nov 2003 11:16:26 -0700, Rich Travsky
<traRvEsky@hotmMOVEail.com> did some sarious thank'n and
scribbled:

You saw that article, I thought it was interesting.

I had several brainstorms while reading it. Since females
are the most dedicated foragers and they are trapped in the
center of the community, then they would overexploit the
center. If males encircling the community could expand and
take over, they may devote their efforts to the best
marginal regions and once complete the females would move to
the new center and the old boundaries would retract and
adjacent chimp communities would move over time.
Alternatively the victorious band could bud backwards
against the adjacent community.
I think this has fascinating ecological consequences
because it gives forest regions time to recover from
continual harvesting. It would be difficult to get all
chimp communities to cooperate in a shift, but via violent
expansion there is a competitive advantage to shifting the
boundaries and thus moving the matriarchal centers. If this
is true then the males do have a valuable function in the
communitie other than providing sperm, the provide the
impetus to move the troup to a slightly new region away from
the previous center and thus 'resting' resting the old
center while getting the childbearers and rearers new
resources.
We can take a look at H/G tribes such as the Baka and
Amazonian tribes that do roughly the same thing. Moving
every year or so to a new site and allowing the old site to
regrow.

This part I don't necessarily accept. From my reading it would appear
that the territory is *usually* relatively static over time. What is
true, though, is that a fission/fusion society requires a much larger
territory than it actively occupies at any point in time. Hence the
border patrols. It is within this larger territory that the
fission/fusion dynamic has the ecologically beneficial spinoff that
you describe. I'm open to correction, of course, but that's what my
reading to date suggests.


Don't overlook the fact that males usually tend to be fiercely wedded
to the *same* territory over many generations, something obvious also
from the human genetics of Europe, Y versus mtDNA. Research seems to
indicate that chimp males would in optimal conditions stick to their
territories.

I had been a supporter of Wrangham and Peterson, but I begin now to
have some doubts regarding how strongly they state their case. Is it
not likely that there is more than one possible "chimpanzee society"?
That the probability of warfare and suchlike represents a cultural
response to ecology, demographics, population density and similar
circumstances? That at least some elements of the societal
organization may be as plastic and as much learned behavior as the
tool cultures obviously are? This might help explain the wildly
different reports that researchers bring back, friendly
group-meets-group carnivals in some cases, deadly warfare in others.
The reality is too sophisticated for a single template.

Of course it remains true that both humans and chimpanzees have at
least a capacity for learning organized warfare.

Harry (Skeptical1)

On 26 Nov 2003 19:36:57 -0800, skeptickal1@yahoo.com

Probable, compare bonobos and chimps and one can see the
minimal range of behaviors in chimps over time; however, it
is unlikely that mating behaviors vary anywhere as large as
humans, so I would think that given you critigue, one can
also think about this relatively

And this would also fall into my scenario, because if
societies became to static, it might be disadvantageous and
reward would go to the troup that bucked the trend; once
again such an advantage would result in boundary shifting.
I don't think the territories of these chimps have been
studied long enough to know just how the borders or centers
shift over time. But if there is fission going on, then
borders must be shifting.

But given the fact that chimps are 2 my diverged from one
end of the population isn't this expected. Now we have a 'giant' chimp.

Why even call it warfare, once you talk about male kin
patriarchies then you are talking about gang on gang. Isn't
this seen with male lions, if a pride of lions can produced
2 or more males of approximately the same age those males
can go out and replace the males in a number of other
prides.

The key ingredient I think that is important that ties these
bands to humans is the cooperation of males to encircle a
community. At the heart of the community something is
happening, and culture can occur. But culture in itself is
not sustainable indefinitely in the status quo, and thus the
males are seeking to expand territories and potentially
bring new females and new culture into their pack, also move
the pack around.
To get from that point to get into tool making humans does
not require anything fancy. Instead of using tools to crack
nuts or grab bugs, you use your tools to make weapons for
expanding your territory and while this is happening the
females back in the camp take the wasted tools or
unweaponizable tools to work foods or wooden objects. This
then evolves on its own. The question is whether bipedality
preceded tool use as being some essential transformation,
bipedality is important, but if male strategies of chimp
shift just a little it might throw selection for hands into
a slight preference for more bipedality, and off you can go.
Take the chimp backward 6 to 7 million years ago, add some
more gorilla and a strong dose of human qualities and then
rethink what might happen. I have often said that
chimpanzees may be an offshoot of larger evolving
population, some extreme that began to specialize too early,
whereas the core population is taking these social
relationships, which we can assume were 100 to 150
individuals in size and working to increase the community
size, at the same time working to increase the competitive
advantage relative to other similar groups.