The average bear, it seems, is getting ever smarter. First, it turned out that at least one can use a comb. Now it appears that some can count, too.
Jennifer Vonk, of Oakland University, in Michigan, and Michael Beran, from Georgia State University, set three American black bears the task of distinguishing between numerically larger and smaller groups of dots (点) on a computer screen. In return for a food reward one bear, Brutus, would touch the more heavily dotted pattern with his nose. The others, Bella and Dusty, would touch the screen with their claws (爪子).
As the researchers report in Animal Behavior, the bears did best with patterns where the coloured dots did not move and where more of them also took up a larger coloured area. This could be explained by the bears' distinguishing the different areas of colour rather than truly counting the dots. However, the three bears managed to pick out the bigger number of dots even in pairs of patterns where fewer dots took up a larger area.
Moving patterns, where each dot followed its own path around the screen, were more of a challenge. But Brutus, at least, was not defeated. He seemed to be counting mobile dots even when the scientists tried to mislead him by moving the total coloured area of the dots at the same time.
It is not entirely surprising that bears should have a high degree of intelligence. They face a lot of challenges when trying to get food. They are, however, always alone, and so do not have the complex social systems that contribute to animal smarts. Perhaps, then, their maths skill developed because they cannot count on their friends for help.
