Early predictors of self-biting in socially-housed rhesus macaques (Macaca mulatta) (2007)

Lutz, C. K., Davis, E. B., Ruggiero, A. M. et al.

Abstract

The subjects were 370 rhesus macaques born at the National Institutes of Health (NIH) Animal Center between 1994 and 2004. They were reared under three conditions: mother-reared in social groups (n=183), peer-reared in groups of four (n=84), and surrogate-peer-reared (n=103). Significantly more surrogate-peer-reared animals self-bit compared to peer-only or mother-reared animals. There was no sex difference in self-biting, but this result may have been affected by a sex bias in the number of observations. The durations of behaviors exhibited by the surrogate-peer-reared subjects were recorded in 5-min sessions twice a week from 2 to 6 months of age while the animals were in their home cages and play groups. In the play-group situation, surrogate-peer-reared subjects who later self-bit were found to be less social and exhibited less social clinging than those that did not self-bite. Our findings suggest that surrogate rearing in combination with lower levels of social contact during play may be risk factors for the later development of self-biting behavior.