Do Rhesus Monkeys Recognize Themselves in Mirrors?

Self-recognition continues to attract attention because of the evidence of a striking difference between the great apes and humans, on the one hand, and all other primates; the former are capable of self-recognition, whereas no compelling evidence exists for prosimians, monkeys, or lesser apes. This is in spite of numerous attempts to facilitate mirror self-recognition in other primates. Although all previous attempts to find self-recognition in rhesus macaques have failed, a recent article [Rajala et al., PLoS One 9:e12865, 2010] claimed the opposite-that adult male rhesus monkeys did recognize their own image in a mirror. We critically examine this claim, and conclude that the article fails to provide acceptable evidence for self-recognition in rhesus monkeys. Am. J. Primatol. 73: 603-606, 2011. (C) 2011 Wiley-Liss, Inc.