Puzzle feeder for great apes (1991)

Shepherdson, D., Gilloux, I., Gurnell, J.

Abstract

The apes could manipulate food items to the end of the pipe by poking sticks through the 2 cm diameter holes drilled along the side of the pipe facing them. When the food items reached the end of the pipe, the animals could reach them with their fingers through the welded mesh. The dispenser was used by all three great ape species and it resulted in more tool use, foraging behaviour and, in some cases, more activity over a substantial proportion of the day.