Figure 2. Red oak gnawing stick being used for
1,2,4, and 5 months by an adult rhesus macaque. Note the small flakes resulting from gnawing.
(Originally published by V. Reinhardt in Laboratory Primate Newsletter 31(2);
copyright 1992 by Brown University. Reprinted with permission of Judith E. Schrier, Editor,
Laboratory Primate Newsletter.
Reinhardt, Viktor. "The Wisconsin Gnawing Stick," Animal Welfare Information Center Newsletter, 7(3):11-12, Winter 1996/1997.