Savanna Chimpanzees Hunt with Tools

So the paper, I mentioned this morning, on chimpanzees hunting with spears has come out… and literally the entire blogosphere I know and track has reported on it. If that’s any indication that this is a remarkable finding to them, then so be it. By the way, Digg loves this news too.

To me this is an interesting finding, but nothing really new.

We have known for a long time chimpanzees use tools in one form or another. Chimpanzee tool use was documented by several primatologists in the field, such as stone tools to crack nuts and sticks used to fish ants and termites. The history, or rather prehistory, of chimpanzee tool use was supplemented with recent archaeological evidence that shows us chimpanzee tool use has been happening for thousands of years.

So what’s the big deal if chimps now also use ‘spears’ to hunt? To me it is just another tool used by a species of primate that has already been well documented as an intelligent organism.

The big deal is the authors of this Curent Biology paper, “Savanna Chimpanzees, Pan troglodytes verus, Hunt with Tools” are claiming the chimps are actually making the spears, and not just selecting for sticks that would be good spears. If this is the case, then this is a critical behavior that distinguishes this form of tool use, from nut cracking. In nut cracking, chimpanzees select for stones that would be more effective in cracking nuts. They don’t particularly make stones that would be good nut crackers. The abstract reflects what they found and I’ve bolded the statements that I feel are particularly outstanding:

“Although tool use is known to occur in species ranging from naked mole rats to owls, chimpanzees are the most accomplished tool users. The modification and use of tools during hunting, however, is still considered to be a uniquely human trait among primates. Here, we report the first account of habitual tool use during vertebrate hunting by nonhumans. At the Fongoli site in Senegal, we observed ten different chimpanzees use tools to hunt prosimian prey in 22 bouts. This includes immature chimpanzees and females, members of age-sex classes not normally characterized by extensive hunting behavior. 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.”

So there you have it, chimps make spears. More over, more female chimps make them than males… I’m sure my physical anthropology professor Adrienne Zihlman would like to read that.

I’ve gathered a list of other blogs who have reported on this paper at the time of my writing of this post, you should have a read and see what other people find interesting.

And from National Geographic News, ‘Chimps Use “Spears” to Hunt Mammals, Study Says‘ as well as a video, ‘Chimps Make and Use “Spears” to Hunt.’ According to the National Geographic News, one of the author’s work, Jill Pruetz, with chimpanzees will be featured in an upcoming NOVA/National Geographic special on PBS but the air date is not yet announced.

10 thoughts on “Savanna Chimpanzees Hunt with Tools

  1. I tried to comment on your first post, but I seem to have screwed something up. I disagree that the Preutz and Bertolani paper is just adding to our existing knowledge of chimp tool use. I blogged it (the advance online publicaiton of the article, not just the news story) here. Who’s using them, how they’re using them, and what they’re making all add to that, but it also has implications for how hominids might have first started using tools.

  2. Matilda, chimpanzees live in a completely different context, from hominids. It’s hard to draw tangents in behavior throughout evolutionary time.

    For example, which chimps are using them doesn’t pan out entirely to all of hominid evolution. Sub-populations of chimps have completely different mannerisms and behaviors from others, so there’s no consistency to say this happened in subsequent hominids… but I won’t rule out the case that hominids that hunted together and cooperated could have been selected for.

    That said, I agree this is an interesting study for the matters you laid out but I think it’s plagued with looking for a adaptation in a related species, which is wrong.

  3. I agree that it’s not as exciting as the pop. sci reports make out. IMO, this behavior is very similar to the termite-fishing that we’ve known about for years.

    However, I do think there are two really interesting aspects of this:

    First – it appears to be a rather detailed sequence of actions to build the tool. This is more impressive than the tool behavior that we’ve seen before, but nowhere near as cool as New Caledonian Crows [1].

    Second – the fact that it’s only been seen in a very small subset of the population suggests that it’s a recently invented cultural behavior. We’ve seen this happen before in food washing behavior in Japanese Macaques [2] and a few others.

    –Simon

    [1] http://language.psy.auckland.ac.nz/crows/
    [2] http://news.nationalgeographic.com/news/2004/02/0206_040206_tvmacaques.html

  4. Kambiz:

    Your points are well taken. Any modeling of early hominid behavior based on extant species is loaded with pitfalls. As you say, their social and ecological context is different, and, of course, they’ve been doing their own evolving for (at least) 4 million years.

    However, chimps and bonobos are our best behavioral models for early hominids and are often used as such. Also, although this spear-using behavior is obviously highly ecologically influenced, if we accept it as a genuinely cultural behavior, then there is no reason that we should view it as entirely ecologically determined, just as we don’t take human cultural behaviors to be simple products of environment.

    In any case, I wasn’t suggesting that this behavior was literally contiguous through time with ancestral populations, more that it speaks to the ingenuity and capacity for innovation in hominoid intelligence and the contexts in which we might have been experimenting for some time.

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