Retrospectacle: A Neuroscience Blog

Researchers have recently discovered that male chimps routinely physically abuse female chimps, sometimes even using branches as weapons. But, why would they do that?

Chimps don’t form monogamous pairs; rather, mating is dictated by the females’ estrus cycles. During estrus, the competition for access to these few fertile females is intense. The leading theory, albeit a shaky one, is that the physical abuse is punishment for female chimps’ promiscuity. By bullying them, they are discouraged from seeking other males, making it more likely that resulting offspring is his. Another explanation is simply that the violence is the result of disputes over food resources.

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To get behind the bullying behavior, a team led by Martin Muller, a biological anthropologist at Boston University in Massachusetts, pooled 7 years of observations of a group of wild chimps in Uganda. The researchers meticulously recorded every push and slap, along with every tryst and pregnancy. Swabbing urine from leaves allowed them to measure glucocorticoid hormones, an indicator of stress.

Male chimps didn’t just beat up on females at random, the researchers conclude. Those that bore the worst of the attacks not only had far more sex–and most often with the males that beat them–but were also the most fecund, with twice the average odds of a sexual encounter resulting in pregnancy. “Males are basically trying to force females into exclusive mating relationships,” says Muller.

However they also found high levels of cortisol–a stress hormone–in the urine of beaten-up females. At persistent high levels, cortisol can result in gastric ulcers and other physical problems, which would be decidedly counter-productive to reproduction.

Muller et al. 2007. Male coercion and the costs of promiscuous mating for female chimpanzees. Proc. R. Soc. B. doi:10.1098/rspb.2006.0206

Comments

#1 J-Dog
February 8, 2007

Damn – I have lots of great snarky comments, but in the interests of PC, my lips are sealed. Regarding the science here, this area is definitely worth a closer look IMO, and results could be very interesting.
#2 Charlie (Colorado)
February 8, 2007

Clear evidence of two things:

(1) chimpanzees lack the forebrain-mediated ability to control impulses

(2) there is a phrase in chimanzee for the word “nag”.
#3 John McKay
February 8, 2007

I don’t know if you should keep your lips sealed, J-Dog. One could make an argument, that is at least as well founded as most evolutionary psychology, that this is the origin of male dominated monogamy, which, as the Religious Right assures us, is the foundation stone of our civilization. From there you could use any one of a number of feminist or marxist social theories to construct a revolutionary manifesto and critique of the violence implicit in the existing social structure. And, it would not necessarily be all snark.
#4 Doug
February 8, 2007

Chimpanzees should be contrasted with bonobos [formerly called pygmy chimpanzees].

Bonobos are a female dominated society.

http://en.wikipedia.org/wiki/Bonobo
#5 Charlie (Colorado)
February 8, 2007

Bonobos also seem to have considerably better parties.
#6 Matt
February 8, 2007

Check out my post on the same topic

http://matt-at-berkeley.blogspot.com/2007/02/does-abuse-pay.html
#7 Shannon Munford
February 9, 2007

This is an interesting study. I suppose a form of anger management therapy could be applied to these aggressive chimps, although traditional anger management treatments do not contain a strong behvaior modification component.

Shannon Munford
Daybreak Counseling Service
#8 Steve
February 9, 2007

Cortisol traps excess belly fat around the middle
#9 er
February 9, 2007

correct me if im wrong, but hasnt the religious right traditionally gone out of its way to say that evolution is bunk and humans are decidedly not descended from monkeys?
#10 Jonathan Owens
February 9, 2007

“correct me if im wrong, but hasnt the religious right traditionally gone out of its way to say that evolution is bunk and humans are decidedly not descended from monkeys?”

It is a straw man argument that the church puts forth – the instinctual drive to dominate women, a very animalistic trait, along with many other less-than-civilized traits..

Hmm.. Maybe the church made a choice many moons ago – “if we defer to nature to explain behavior, people will defer to nature and worship it rather than us”

You couldn’t have ever built civilization (as we know it) with nature worship.
#11 feminazi
February 9, 2007

I have long suspected that male violence toward females results in a positive social outcome for males, and is why male-on-female violence was never taken seriously for thousands of years. Males have always possessed the desire to control female reproduction and they use violence or the fear of violence as a control mechanism.

I really didn’t require a study to explain this, but probably other people do, so thanks. Perhaps if male chimps could develope an artifical womb and make their own children would they finally stop trying to control females’s lives. But then they’d probably just sell the baby female chimps to other males and abuse them.

Males suck. Truth hurts. Deal.
#12 fred lapides
February 9, 2007

A guess: the male chimps are showing a closeness to being human and seek a means of monagmous relationships, the goadl (fruitless?) of the human species.
#13 mullingitover
February 9, 2007

Chimps are pimps?
#14 kuanchaiken
February 9, 2007

why some people conclude that the beating has to do “forcing females into exclusive mating relationships”?

does this thinking imply that male chimps have the concept and the wish for monogamous relationships? and female chimps either don’t understand it or just refuse (in the name of freedom or lust, if you are modern or old fashioned)?

since we all like to draw conclusions out of facts we don’t know, i will propose that males beat the females to make them mate out of simple fear and dominion.

i find it a simpler and less antropomorphic theory. the only flaw is that it’s obvious.
#15 Joy Spoiler
February 10, 2007

Given the overrepresentation of radically political women in the biological sciences, emphasis on this sort of research never really surprises me. I’m really tired of science as victim narrative in anthropology. Scientists make distinctions between things that are different. Phrases like “domestic violence in chimps” are anthropomorphic fallacies and inappropriate value judgements that confuse people who aren’t trained to make such distinctions.
#16 bernese
February 10, 2007

feminazi: What about the other species of chimpanzee, the bonobo, who have a matriarchal and egalitarian society? Humans did not evolve from chimpanzees, rather humans and chimps share a common ancestor. Our behavior is not evolutionarily derived from either the common chimpanzee studied in this article or the bonobo, and if we are otherwise looking for guidance from our close relatives we have two distinct and contradictory cultures. What about the instances of matriarchal human societies around the world? Also, the supposition that violence and oppression towards women results in a positive outcome for males is idiotic. A society where roughly half the adults are treated as sub-humans is not competitive with one where everyone is granted equal rights and the opportunity to contribute wholly.
#17 Shelley
February 10, 2007

Now, it seems that a fair number of people are reading a bit too much into the study. For one, male-on-female violence exists in many species, but of course it is only humans’ point-of-view by which it is considered “violence.” It is the way of life, and how many species evolved. So, yes, I agree that anthropomorphizing doesn’t accomplish much here, insofar that it isn’t behavior that should be “corrected” per se. On the other hand, this research didn’t have an agenda. It was done by a (mostly) male team who happened to observe behavior and became curious as to its etiology or reproductive advantage.

The male chimps aren’t beating the females out of some sense of vicious malice or degeneracy, but because this behavior has been reinforced over a long period of time to confer (some kind) of reproductive advantage. And what that advantage might be, we can at this point only speculate.
#18 Tom Wolfe
February 11, 2007

So if if someone beats the shit out of his girl friend, so what?

Hes wired that way!
#19 speedwell
February 14, 2007

Hes wired that way!

So far, we only know this is a fact if he’s a chimpanzee. Do pay attention.
#20 aut
March 3, 2007

I am not sure what your post is trying to say. Violence, abuse , hatred sex, know no sex, no color, no bank account, it reaches all corners of the world and touches as close to your as your own living room.

SB: The post is reporting on scientific study and makes no claims about human behavior.