From Philip Stewart
Nick Sibbett recalls a record of tool use by a chimpanzee dating from the 1920s (2 July, p 22). I remember reading as a child about an orang-utan that bent a piece of wire to pick the lock on its cage. It was in a Children’s Encyclopaedia – I think the 1910 edition handed down by my father. Does any reader happen to know the exact reference?
Oxford, UK
