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If animals indeed have the capacity to understand and manipulate symbols, the question then becomes why and when did they develop it. For answers, scientists have turned once again to chimps, who both in the wild and in captivity show the ability to formulate plans and make tools. Kanzi has been most helpful in this regard.
In an experiment supervised by Nicholas Toth of Indiana University, Kanzi watched as a favorite treat was placed inside a box. The box was then locked, and the key was placed inside another box tied up by a cord. It added up to a Houdini-like challenge for the chimp: how to get to the treat.
But inside his cage, Kanzi had the makings of a tool that could solve the riddle: some pieces of flint he had selected during an excursion to the countryside. No sweat! By slamming the flints against the concrete floor, the chimp created knifelike chips, which he used to cut the cord and free the key. He then used the key to open the other box and grab the treat.
Toth notes that in several runs through the experiment, Kanzi always used the chip to cut toward himself, an observation that might help Toth better understand the first tools of Homo habilis some 2 million years ago. "For a Stone Age archaeologist like myself, seeing this is almost like a religious experience," says Toth, whose university awarded Kanzi a prize for providing the most insight into the origins of technology.
Observations of apes in the wild provide further insights. In the Tai forest in the Ivory Coast, Swiss biologist Christophe Boesch points out a flat piece of granite with two small hollows on the top. The rock has marks from heavy use for some purpose. "If an anthropologist came upon this in the forest," says Boesch, "he might think he had found a human artifact." Instead, it is used by chimpanzees for nut cracking. The chimps place a panda nut in one of the depressions and then smash it with a smaller stone. Boesch has watched a mother chimp instruct her young in the art of nut cracking.
Still, toolmaking does not entirely explain why apes, humans and other animals developed big brains. Gorillas, orangutans and bonobos are roughly the intellectual peers of chimps but rarely resort to tool use. Nor does the need to build tools fully account for the enormous expansion of human brainpower during the past million years. As recently as 100,000 B.C., Homo sapiens were using only the crudest tools, even though their brains had already reached the present size -- large enough to put men on the moon, probe the basis of matter and tinker with the genetic code. Because big brains need a lot of high- calorie food and require large craniums, which makes childbirth difficult, scientists have looked for other evolutionary pressures to account for their development.
Machiavellian Chimps