Mirror-image reactions in a tool-using, adult male Macaca tonkeana

This study examined reactions to mirror-image stimulation in a wild- reared adult male monkey (Macaca tonkeana) which had spontaneously developed a form of tool-use, namely the use of plant stems to reach mucus inside the nose. Initial intense social responsiveness to the mirror was followed by habituation, although some social responding persisted. Mirror- induced social facilitation of drinking was demonstrated, the first record of such an effect in a nonhuman primate. Rather than enhancing the subject's tool-using activity, the presence of the mirror disrupted tool-use. Finally, an objective test for the presence of self-recognition failed to obtain any evidence of self-recognition in the subject, lending support to the view that the capacity for self-recognition may be lacking in monkeys.