The Wisconsin Gnawing Stick (1997)

Reinhardt, V.

Abstract

The sticks consist of branch segments cut of dead red oak trees. They are used by caged macaques about 5% of the time - more by young animals, less by adult animals - for gnawing, manipulating and playing. All caged rhesus macaques (more than 700 animals) and all caged stumptailed macaques (approximately 36 animals) have continual access to gnawing sticks since that time [1989]. ... Long-term exposure to the sticks has resulted in no recognizable health hazards.