W.W. NORTON, APRIL 2016One early November morning, while the days were getting colder, I noticed that Franje, a female chimpanzee, was gathering all the straw from her bedroom. She took it under her arm out onto the large island at the Burgers’ Zoo, in the Dutch city of Arnhem. Her behavior took me by surprise. First of all, Franje had never done this before, nor had we ever seen other chimps drag straw outside. Second, if her goal was to stay warm during the day, as we suspected, it was notable that she collected the straw while at a cozy temperature inside a heated building. Instead of reacting to the cold, she was bracing for a temperature she could not actually feel. The most reasonable explanation would be that she extrapolated from the previous shivering day to the weather expected today. In any case, later on she stayed nice and warm with little Fons, her son, in the straw nest she’d built.
I never cease wondering about the mental level at which animals operate, even as I know full well that a single story is not enough to draw conclusions. But those stories inspire observations and experiments that do help us sort out what’s going on. The science fiction novelist Isaac Asimov reportedly once said, “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny.’” I know this thought all too well. We go through a long process of watching our animals, being intrigued and surprised by their actions, systematically testing our ideas about them, and arguing with colleagues over what the data actually mean. As a result, we are rather slow to accept conclusions, and disagreement ...
