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Don’t be a tool!

June 12, 2009

In the early ’60s, Jane Goodall rocked the scientific world when she reported that chimpanzees use tools. Chimps were taking advantage of the fact that termites bite and hold on to anything invading their mound—even if it means being dragged out of the mound. So the chimps figured out that by poking long twigs and bits of grass into the entrances of termite mounds, they could score a tasty termite kebab.

This termite fishing qualifies as “tool use” because the chimps use an object to alter the condition of something else. Sounds simple, but it’s kind of tricky. Ya see, lots of animals use objects they find in their environment to get food, but it doesn’t always count as “tool use.”

Huh?

Exactly. Here’s the deal: if an animal throws a rock at its food—as Egyptian vultures do to crack open ostrich eggs—then it counts as tool use. BUT, if an animal throws its food at a rock—as bearded vultures and golden hawks do with tortoises—it does not.

That distinction might seem a little nitpicky, but it’s backed by hard science. Researchers found that the part of the brain* responsible for the ability to use tools is actually bigger in animals that use tools than it is in those that are just borderline users (e.g. those that bash their food against something hard).

Case in point: one of the best tool users around has one of the biggest brains relative to its weight—the crow. Most members of the crow family (family Corvidae) are what some would call “downright clever” (and what we call “freaking smart”). When a crow was given food that wasn’t up to snuff, it took matters into its own…umm…hands. A researcher had forgotten to wet the corn meal before feeding it to one of the crows in the lab. Instead of choking down the dry corn meal, the crow used a random cup in its cage to fetch water from its water spigot in order to prep its own meal. (According to the researchers, the cup was only in the cage as a random object and had never held water before.)

A more recent example involves a study of rooks (a close relative of crows and magpies). The birds not only knew which tools were right for a job, but figured out how to use multiple tools in sequence. In the experiment, the birds were presented with a tube leading to a trapdoor that held a tasty worm. By dropping a stone down the tube, the birds opened the trap door and out dropped the worm. When presented with a wide-mouthed tube, the birds chose the largest stone available—they were offered three different sized stones. But, when the tube was narrower, the birds went right for the smallest stone, which was the only one that would fit down the neck of the tube. (Check out the video here.)

Now comes the freaking smart part. The rooks were presented with two tubes, a narrow one holding a worm and a wide one holding a small stone. The birds dropped a large stone down the wide tube, releasing the small stone. Then, they picked up the small stone and dropped it down the narrow tube, releasing the worm. In a separate set of trials, the rooks were given a wire instead of a set of stones. On their very first try, they figured out that they needed to bend the wire into a hook to get the worm at the bottom of the tube. For the record, the birds had never been taught to bend the wire. (Check out that video here.)

Screw the early bird. Clearly, it’s the tool user that gets the worm.

* In mammals, the neocortex is the hotspot for tool use (and sensory perception, spatial reasoning and parts of short-term memory). Birds have a different brain structure, and the important regions are called the mesopallium and a midopallium, in case you were wondering.

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