Humans depend mostly on visual cues, while other species use olfactory or auditory methods.
Chimpanzees, like humans, also depend on visual discrimination. According to a report in the June 17 issue of Nature , chimpanzees can easily recognize faces of their brethren presented in digitized photographs. This ability to discriminate one group-mate from another has helped chimpanzees evolve to form the most complex of all mammal societies, characterized by individualized relationships, cooperative networks, and stable hierarchies of power. In Nature , Living Links Center researchers at the Yerkes Primate Center, Lisa Parr and Frans de Waal, describe the first evidence in primates for an extension of these face recognition abilities to kin recognition that is purely visual and independent of previous experience with the individuals in question. Parr and de Waal demonstrate that chimpanzees, using a computerized joystick program, are able to accurately match portraits of unfamiliar females with their sons.