Shadows of Forgotten Ancestors

Baboons in Gombe eat termites, but almost entirely during the two- or three-week period in which the insects migrate. Then the baboons can be seen gathering and slurping the insects, and leaping into the air to catch them on the wing. In less bountiful times, baboons will be shooed away from a termite mound by an arriving group of chimpanzees. Sometimes the displaced baboons sit a little distance away, morosely observing the chimps working away with their tools on the mound. When the chimps are done, they leave their modified stalks and reeds at the base of the mound. But no baboon has ever been observed trying to use an abandoned tool—even though it could extend their termite season from weeks to months. Apparently the baboons just don’t have it in them. They’re not smart enough. Probably their brains are too small.

As chimps are much better than baboons at collecting termites, so some preindustrial humans who routinely eat termites are much better than chimps. They dig open the termite mounds, or fumigate them, or flood them with water. One of the more elegant practices is—with the tongue on the palate, or two pieces of wood gently touched to the mound’s surface—to imitate the sound of raindrops, which entices the termites out of their nest.¹³

Chimps have never been observed to use these techniques.* Probably they’re not smart enough. Probably their brains are too small.

What we find most interesting is the overlap. Some chimps lack even probe technology, and are no better at catching termites than baboons are. Other chimps are armed with a well-developed if rudimentary technology, many steps having to be done correctly and in the right sequence for the method to work—as good as many human cultures, although nowhere near as good as some. There are human cultures barely up to the highest chimpanzee standards of termite catching, and others only on a par with the baboons.¹⁵ No sharp boundaries are apparent here separating baboons from chimps, or chimps from humans.

Chimps also drop branches on intruders and sop up drinking water with leaves. While they cannot be described as fastidious or obsessively hygienic, chimps are known to use leaves as toilet paper and handkerchiefs, and twigs as toothbrushes. They employ sticks for digging up roots, for investigating animals in burrows and knotholes, and—like a croupier at a gaming table—for raking in otherwise inaccessible fruit. If they were able to manufacture more complex tools, they certainly would have the intelligence and dexterity to use them: In zoos, chimps try to steal the keys from the keeper’s pocket. When successful, they often manage to open the lock. Like us, they can sometimes use their intelligence to escape from bondage.

Male chimps like to throw missiles—whatever is handy, generally sticks and stones. (Like the inmates of college fraternity houses, they also occasionally throw food.) Females are much less interested in missiles. Chimps would throw stones at the visitors who gawk at them in the traditional kind of zoo—if they had stones. As it is, all they have is feces. When wild chimps are presented with a fairly realistic mechanical leopard, after a reassurance frenzy of screams, hugs, and mutual mountings, they find appropriate clubs and beat the effigy to death—or at least until they knock the stuffing out. Or they’ll pelt it with stones. (In the same circumstance, baboons will furiously attack the leopard, but without a thought of using clubs. Baboons just don’t know about tools.)

Chimps have stunned or killed by throwing stones. The directionality of their throwing is good. Where they’re deficient is in range: In tense confrontations with prey or hostile peers, thrown rocks hit their targets only a few percent of the time. Adolescent boys don’t do much better under comparable conditions. But even when inaccurate, a hail of stones can be off-putting.

A distinction needs to be made between tool using and tool making

. Many scientists have conceded tool use to other animals, and, following Benjamin Franklin, defined humans as the sole tool-making animal; where tools are manufactured, it is suggested, language cannot be far behind.¹⁶ But the chimpanzee termite fishery industry makes it clear that chimps, with considerable forethought, both make and use tools. Chimps also have a rudimentary stone technology, although, as far as we know, they don’t manufacture stone tools in the wild. In captivity, though, Kanzi—the linguistically talented bonobo—has, imitating human models, hit stones together to produce sharp flakes, which he then uses to cut a string so he can open a box which is filled with food. (This is a causality sequence at least five steps long.) As long as it’s sharp enough to cut the string, Kanzi will generally settle for the first crude stone knife he flakes off. But the thicker the rope he must cut, the larger and sharper the knife he makes.¹⁷