Chimpy See, Chimpy Do

2/20/2007

Ever on top of things, I want to talk about an item in the news last week: The discovery of chimpanzee stone tools dating back 4,300 years. Here are a couple stories about the discovery: Link. Link.

The fact that chimpanzees in some habitats use stone tools is not news. In fact, chimpanzee tool use has been long known to evolve in habitats where there is selection pressure in its favor: In other words, where there is necessity to midwife the invention.

The findings in the Tai National Park in Ivory Coast demonstrate a 4,300-year-old material culture for our closest living relative. A prehistoric chimpanzee stomping ground? That is just too fascinating, as is the notion of a chimpanzee material culture,'' a term from human anthropology about the study of our tools, textiles, and clay pots. It makes complete sense, but I'd never really thought about it before.

But what really struck me about these reports is the assertion that this discovery well, let me quote the National Geographic article on the subject:

The research pushes back chimpanzee tool use thousands of years. It casts into doubt the longstanding theory that direct human ancestors were the only animals to independently develop tools and that chimps learned to use stone tools by watching humans. (emphasis is mine.)

What? There was a longstanding theory that if it wasn't for humans, chimps wouldn't have made it into the stone age? Does this strike anyone else as a wee bit anthropocentric?

We we watch films of chimps reconciling after a fight and then feel proud of how we taught them this peacekeeping behavior? We certainly don't look at their warlike behavior, their violence toward outsiders, and feel bad about our influence. Why would we look at tool making any differently?

Chimps in zoos can learn a lot of things from humans. They can learn sign language, and they can even learn to hit nuts with rocks, but I don't find this very convincing evidence of chimps in the wild copying human behavior. That they have an ability to learn from one another is well known. That baby chimps learn how to crack nuts with stones by watching mother is often seen. That chimps can learn by observing humans, I don't doubt. But evidence that the skills they use in the wild come from us? I don't know of any. And in fact, the simplest explanation, the most straightforward explanation, the one that does not require chimpanzees crouching in the bushes and, at considerable risk to themselves, watching humans use stone tools, and then brachiating home all in a lather to try it themselves, is the explanation that chimps, on their own, simply happened upon the discovery that a rock can break open a tough nut.

That human influence on chimps is the default explanation of chimp tool use just seems ... well, like we should get over ourselves already. Who knows, we're a pretty smart species. Maybe we had the sense to copy from chimps.