Fish, mirrors, and test of self-awareness

Scientists at the Max Planck Institute claim that fish have passed the ‘mirror test’. Cleaner wrasse, just a few centimetres long, are the first of their kind to do so and must now be admitted to an exclusive animal club, to which only self-aware creatures belong, writes Richard Collins.

On a visit to London Zoo in 1838, Darwin befriended Jenny, an orang-utan. On seeing her image in a mirror, she seemed to recognise herself.