CHICAGO — Give the chimpanzees living at Uganda’s Toro-Semliki Wildlife Reserve a hand for having the mental moxie to dig water-collection holes along the edge of a river that flows only during rainy months. In fact, give them two hands, because wells dug by these chimps show no evidence of having been fashioned by either right-handers or left-handers, according to anthropologist Linda Marchant of Miami University in Oxford, Ohio.
Evidence of ambidexterity in Semliki chimps counters a suggestion from other researchers, based largely on studies of captive animals, that chimps often favor one hand over the other when performing various tasks. If it exists, chimp handedness interests researchers because it may reflect an evolutionary move toward a brain organized more like that of people — with one hemisphere dominating over the other and prompting either right- or left-handedness —than has often been assumed.
“We see no