Table 4.

Prevalence of various abnormal behaviors in chimpanzees in other published studies

	1 or more abnormal behaviors (including coprophagy)	1 or more abnormal behaviors (excluding coprophagy)	Coprophagy	Hair plucking (self or other)	Regurgitation and reingestion
Current data (research facilities)	37.1%	32.5%	10.0%	8.8%	7.7%
Reference 4 (research facilities)			33.2%	22.4% (maximum possible)	5.6%
Reference 12 (zoos)	100.0%		83.0%	78.0% (maximum possible)	30.0%
Reference 54 (zoos)	64.0%	48.0%	41.0%	32.0%	7.0%
Reference 56 (former research animals)			72.0%
Reference 68 (former research animals)			37.7%