February 23, 2007

Chimps hunting bushbabies

Mixing Memory has an interesting post about our closest relatives . . . the chimpanzees! Well, a journal article has recently been published that describes a case of tool use in chimps. But not just the normal, "stick a twig in a mound of dirt to gather termites" type of tool use. No, this is complex tool use that has not been witnessed in chimps or other non-human primates before. They use tools for hunting!

Now the creation and use of tools for hunting was thought to be uniquely human. Well, I guess that changes now:

"Chimpanzees made 26 different tools, and we were able to recover and analyze 12 of these. Tool construction entailed up to five steps, including trimming the tool tip to a point. Tools were used in the manner of a spear, rather than a probe or rousing tool. This new information on chimpanzee tool use has important implications for the evolution of tool use and construction for hunting in the earliest hominids, especially given our observations that females and immature chimpanzees exhibited this behavior more frequently than adult males."
Now, just what did these chimpanzees hunt with their "spears?" Why, bushbabies of course! You're not sure what a bushbaby is, are you? It's one of these little guys:

"In all observed cases, chimpanzees used one hand in a “power grip” [17] to jab the tool downward multiple times into the cavity. In the single instance in which a chimpanzee was observed to extract a bushbaby, it was unknown whether the prey was alive or dead after the use of the tool, but it made no attempts to escape, nor did it utter any vocalization."
Ouch! Kind of makes you feel a little sorry for the little buggers. In all, this seems to be a pretty important study into the chimp culture and perhaps has implications for the evolution of hunting. Some things that I would like to know is whether bushbabies are the only prey, for which they use these spears, or do they also hunt small rodents and what not. Is this a select incident or special case? Will we eventually find that this is a common trait among all chimps? I'm not really too familiar with the literature on chimpanzees, so perhaps I should look some of this stuff up?

Well, if you are interested, the original journal article can be found here at Current Biology.

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