Bonobos are the only species of great ape for which there are no data concerning self-recognition. Although there is little evidence reported for self-recognition in New or Old World monkeys (see Anderson, 1984; Boccia, SAAH23; Thompson & Boatright-Horowitz, SAAH22), mirror image stimulation (MIS) has been established to elicit behaviors indicative of visual selfrecognition in humans, chimpanzees, orangutans, and gorillas (see Gallup, 1987; Lewis & Brooks-Gunn, 1979, for reviews; Miles, SAAH16; Patterson & Cohn, SAAH17). In an effort to determine to what extent, if any, visual selfrecognition exists in bonobos, a study was conducted at the Yerkes Regional Primate Research Center main station and at the Yerkes field station.

Bonobos have until recently been classified as pygmy chimpanzees, but closer examination has revealed significant differences between what are now recognized as two distinct species of the genus Pan (see reviews by Susman, 1984; de Waal, 1991). Bonobos are physically smaller, walk bipedally more often (Doran, 1992), and exist in larger and more sexually active social groups than do “common” chimpanzees (Kano, 1982). Bonobos also exist in smaller ranges and total numbers in the wild than do chimpanzees, and so their exposure to and interaction with humans has been limited. Less than fifty bonobos are currently in captivity in the United States. The language-trained bonobos Matata and her son Kanzi (see Savage-Rumbaugh, 1986) have been observed by the authors to engage in mirror-aided grooming of their teeth and heads; yet until now, no controlled studies have been conducted on selfawareness in bonobos.