Variables influencing the origins of diverse abnormal behaviors in a large sample of captive chimpanzees (Pan troglodytes) (1999)

Nash, L. T., Fritz, J., Alford, P. A. et al.

Abstract

Rocking and self-sucking were significantly more likely in hand-reared animals. Coprophagy and depilation of self were significantly more likely in mother-reared animals. ... The only significant sex difference was a higher prevalence of coprophagy in females and a higher prevalence of rocking in males. ... Abnormal behaviors acquired from other chimpanzees through social contacts may not be indicative of reduced psychological well-being.