Posted on 06/21/2010 6:34:12 PM PDT by Willie Green
Chimps, just like humans, kill each other for territory, researchers have found.
“Chimpanzees kill each other. They kill their neighbors. Up until now, we have not known why. Our observations indicate that they do so to expand their territories at the expense of their victims,” said John Mitani of the University of Michigan, a member of the research group.
The slayings usually are committed by small groups of males on patrol, said the scientists. But unlike in much human warfare—where armies are sometimes willing to attack other, comparably sized armies—the chimp killers specifically seek out lone or badly outnumbered victims for an easy ambush.
Common chimpanzees are one of the two species with the closest evolutionary relationship to people. Scientists believe that traits shared by chimps and humans were likely possessed by the common ancestors of both. Thus some researchers say the motives and methods of chimp violence may shed light on how human violence evolved.
Yet Mitani and colleagues argue that studies of chimp aggression will reveal more about why humans so often work together than about why we do battle. “Using our results to address an enduring question about why humans are an unusually cooperative species may prove to be a more productive line of inquiry,” the researchers wrote.
Their findings are reported in the June 22 issue of the research journal Current Biology.
Mitani and colleagues studied chimps living in Ngogo, Kibale National Park, Uganda, which have been under observation over a decade. During that time, a team directed by Mitani and David Watts of Yale University documented 21 killings by the Ngogo chimps of individuals from other groups. Eighteen of those killings were seen directly, while the rest were deduced from circumstantial evidence.
The researchers think up to 13 of the victims belonged to a single neighboring group, representing an “extremely high” rate of mortality due to violence among groups.
With some of their competitors out of the way, the Ngogo chimpanzees began to use a large portion of new territory to the northeast of their previous range. “Because the newly acquired territory corresponds to the area once occupied by many of the victims, we suggest that a causal link exists” between the violence and the territorial expansion, Mitani said.
Mitani and his colleagues think the new territory most likely benefits the chimps by affording greater access to food. It may also ultimately lead to greater access to females, but it’s too early to tell, the scientists said.
The attacks are triggered when bands of chimpanzees go out “on patrol” into the territory of a neighboring chimpanzee community, the researchers added. “Patrollers are quiet and move with stealth,” Mitani said. “They pause frequently to scan the environment as they search for other chimpanzees. Attacks are typically made only when patrolling chimpanzees have overwhelming numerical superiority over their adversaries.”
The Ngogo chimps may have an unusual advantage over their neighbors due to the impressive size of their community, which may explain the surprisingly high level of violence, the researchers say. There are more than 150 Ngogo chimps—about three times the number found in chimp communities studied elsewhere.
The study could shed light on how cooperation evolved among humans and related species, Mitani and colleagues said. This is because brutal as the chimp slayings may be, they illustrate how animals cooperate for the benefit of their group.
“Our observations indicate that territorial conflict leads chimpanzees in some groups to cede land to members of other groups as a consequence of lethal coalitionary aggression,” the researchers wrote. “In the process, chimpanzees in communities that gain territory obtain increased access to resources that are then available to others in the group.”
The evolutionary question is whether these benefits outweigh the costs for individual chimps; if not, it’s hard to explain how such cooperative behavior could have evolved, Mitani noted.
Must be western chimps or hungry, unemployed chimps without health care.
One can definitely see the same behavior at work among some so-called “human” groups...
My guess is that they’re Liberal RAT chimps.
Wait! I thought man was the only species to kill each other over resources like territory or food... This cannot be!
Have they stopped doing the ‘survival of the fittest’ lectures in school ?? This is surprising how ?
If you want to study chimps for whatever reason, ok I guess. But spending 10 years observing and then making up theories that seem like they were formulated in 5 minutes tells me that most of what these people are doing is a complete waste of time. And trying to find some corollary between the chimps and human behavior is absurd.
““Chimpanzees kill each other. They kill their neighbors. Up until now, we have not known why. “
And they call them scientists.
I am reminded of 2001: A Space Odyssey.
In the beginning scenes two different groups of monkeys are fighting in a territorial dispute.
I find it hard to believe a ‘scientist’ never saw the movie.
Or reruns of the old TARZAN AND JANE movies (especially the b/w ones)
Go to the ant, thou sluggard; consider her ways, and be wise. - Proverbs 6:6
They’re not monkeys.
Must be that “evolved morality” we keep hearing about.
“chimp killers specifically seek out lone or badly outnumbered victims for an easy ambush.”
“One can definitely see the same behavior at work among some so-called “human” groups...”
Like SEIU or Inner City Yoots.
I'm no scientist, but I suspect it's because they want them dead.
Probably chimps without rail access since Willie Green is the poster!
I have a soft spot for most beasts, but I sure do not like chimps. I know, that has nothing to do with the thread, but I just had to say it.
Sounds like these guys haven’t studied much animal behavior at all. I mean, c’mon for pete’s sakes, look at wolves, dogs, lions, even moose, elk and deer will pack up and kill a foe, even ants.
Where have these guys been? Sounds like we wasted a lot of money sending a bunch of community agitators, rather than scientists to Uganda.
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