Chimpanzees and other great apes get all the good press when it comes to the intelligence of non-human animals. Chimps use tools and teach their offspring to do so, for instance, whether it's twirling a stick into a termite nest to extract hors d'oeuvres or selecting just the right rock to crack open a tough nut, as researchers keep discovering.
Scientists are reporting today that New Caledonian crows are no slouches when it comes to sophisticated tool use. As they report online in the journal Current Biology, the crows can spontaneously combine two tools to get a snack--and in a way that suggests they solved the problem not by trial and error, but by reasoning through analogy. That is, the crows were able to see that a novel situation was essentially the same as one they'd encountered before.
"Evidence suggests that, from the earliest human stone tools, analogical reasoning has been at the core of human innovation," Russell Gray of the University of Auckland, who led the study, said in a statement. "This hallmark of human intelligence may also be at work in both the great apes and New Caledonian crows."
In the study, the researchers put food in a hole that was unreachable unaided. They also left a stick lying around, but it was also too short to reach the food. They left one more prop: a long stick in a "toolbox." This stick was long enough to reach the food--but it, too, was out of reach. No problem. The crows used the short stick to get the long tool out of the box, then used the long stick to get the food. In fact, six out of seven crows immediately tried to get the long stick with the short stick; only one dunce did the bird-brained thing of trying to get the food directly with the short stick and realizing that wouldn't work, and that he had to use the short stick to get the long stick.
Next challenge: food still at the bottom of a deep hole, small stick inside the toolbox and long stick within the crows' reach. The crows briefly used the long stick to poke the toolbox, but immediately saw their mistake and then just carried the long stick directly to the hole to fish out the food. They did not brainlessly apply the rule, "use available stick to acquire hidden stick and then proceed to food hole," but instead scoped out the situation and employed the most efficient algorithm for getting their snack--in this case, "forget about out-of-reach long stick, and notice instead that available short stick is all I need to fetch food."
It's fascinating to think about the evolution of intelligence, and perhaps a measure of our collective ego that we fancy only we have it, withour direct ancestors and perhaps a few cousins having pale shadows of it. Clearly, as the continuing research on animal intelligence shows, that is not the case.