TOOL-USING IN JAPANESE MACAQUES - USE OF STONES TO OBTAIN FRUIT FROM A PIPE

Tool-using behaviour was studied from 1983 to 1992 in a provisioned troop of free-ranging Japanese macaques, Macaco fuscata, at Jigokudani Monkey Park, Japan. The macaques were given a series of instrumental conditioning trials in which they were trained to use sticks to remove an apple from a transparent pipe. Subsequently a female named Tokei invented the technique of throwing a stone under-hand into the pipe to get the apple, and the same technique was later adopted by two other females and a male. These females did not throw stones at random, but selected those of a particular weight before throwing. Tokei also made her infants enter the tube to obtain apples, and she varied the momentum of throwing stones to prevent other macaques stealing the fruit from the other end of the pipe. © 1993 The Association for the Study of Animal Behaviour.