Wednesday, February 25, 2009

Bonobos hunt, eat monkeys

Bonobos have been popularized by many to be a peace-loving species. They've been called the "Make Love Not War" ape. They've been held up for contrast with chimpanzees, a very closely related ape biologically-speaking, but one that is very different behaviorally. Chimps are strongly male dominant and are physically violent to the point of engaging in deadly gang-style warfare with their neighbors. Plus, they assemble organized male hunting parties that target monkeys. Red colobus are their favorite prey. They share the meat too, favoring their allies and friends. Bonobos, in contrast, lack male dominance (about half of troops are female-led) and are far less physically violent with each other, preferring to solve conflicts through other means. They've never been observed perpetrating gang warfare on neighboring troops or hunting meat, let along eating it.

Now, two reports have been published that may upset what was understood to be unique about bonobos. One study reports that researchers combed through wild bonobos' poo and found something surprising — monkey bones. Picking through monkey doo may not be a glamorous job, but it is the best way to find out what primates actually eat. It turns out bonobos eat monkeys. The other study reports that research actually observed their hunts.

Five hunts were observed. Three were successful and 2 of the 3 kills were made by females. It's a small sample of hunts so it's really not enough to decide whether there is a sex difference in hunting. But, if there is, it would stand in stark contrast to chimpanzee hunts which are overwhelmingly male affairs.

Time will tell whether this milestone research changes what we think of bonobos. Perhaps they'll shed some of their peaceful reputation — or maybe they won't. After all, just because you eat meat doesn't mean you're violent.

Current Biology. 2008. Primate hunting by bonobos at LuiKotale, Salonga National Park.

Folia Primatologica. 2008. New Records on Prey Capture and Meat Eating by Bonobos at Lui Kotale, Salonga National Park, Democratic Republic of Congo.


Cecile/DreamCreateRepeat said...

Interesting post. I guess observations are like any other sampling: the more you sample (in this case, observe) the more accurate the conclusions....

Is that an argument for better funding for scientific research!?! ; )

Carapace said...

This latest bit of research-- and I've heard it on NPR, too, and read it on some other science blogs-- confuses me. (a) I'd always heard bonobo were entirely matriarchal, like ringtail lemurs and (b) who the heck ever said bonobo don't hunt?!? Even deer will eat things like bird eggs, when they can get them. Meat is just a very high-value food source.
Also, why should hunting be considered a sign of violence? Group hunts are bad news for the prey, of course, but are a good sign of cooperation and community among the hunters.
I wonder, are the conclusions (oh, no, bonobo must be violent!) I've been hearing the conclusions of the reporting scientists, or just the way the secondary reporters try to make it exciting? Do you know if there's somewhere I could read the papers in question?

Field Notes said...

I agree with you Carapace - group hunts are cooperative and do engender a sense of community when the meat is shared, as it often is, at least among chimps.

Unless you are affiliated with a college or university that carries the journals Current Biology and Folia Prmatologica, or can get them through ILL, it will be next to impossible to actually read the reports.

I even have to request Folia Primatologica through ILL since my library doesn't carry it!

However, some researchers are able and willing to share their publications with you if you write to them and ask.

I've added clickable links to the article references at the bottom of my post so you can track down the authors and their addresses and write to them =D

Luella said...

I disagree that hunting is not violent. No, it's not really a sign of aggression, per se, but it is nonetheless doing a violence to the animal being eaten. Otherwise, let's go on and pretend that lions are not at all a violent species except for when that attack hyenas for being pesky. Everyone thinks of lions as "ferocious" and violent because they EAT HUMANS. My point is, if you were a monkey being hunted by bonobo, you would not for an instant think that a bonobo was nonviolent. I'm afraid that there's some meat-lusting bias going on here. Love does not mean there's no violence. If Hitler loved someone or cooperated with his generals, that would not have made him nonviolent. Simple as that.

Also, what difference does it make if deer eat bird eggs? That may or may not be a violence, but if it is, do you think they're aware of it? I don't. I don't think they're aware that eggs have life in them. They're not even hunting. Let's say we call them violent for the sake of consistency... well, in the process of stealing milk from cows, humans feed cow blood to calves through a machine. What difference does that make? They didn't even have a choice in the most remote sense. Bad comparison, I dare say.