Credit: Neng Gong and colleagues/Curr. Biol. Macaques can be trained to recognize themselves in a mirror, the first such observation in any monkey species.

Most animals encountering their reflections act as if they are seeing another creature. To find out whether monkeys can be trained to recognize their own reflections, Neng Gong and his team at the Shanghai Institutes for Biological Sciences placed rhesus macaques in front of a mirror and shone a low-powered laser beam on their faces to produce a mild heat irritation. They rewarded animals when they touched the irritating spot on their face (pictured).

After 12 to 38 days of this regimen, 5 out of 7 macaques using the mirror touched an odourless mark applied to their faces. With a mirror in their cages, some of these monkeys seemed to use it to explore parts of their bodies that they could not otherwise see. It is not clear, however, whether these behaviours mean that the monkeys have higher cognitive abilities such as self-awareness, the authors say.

Rights and permissions Reprints and Permissions