Effects of hand-rearing on the reproductive success of western lowland gorillas in North America

Abstract

This study sought to assess the potential effects of hand-rearing by evaluating the relationships among rearing type and reproductive success in the American Zoo and Aquarium Association's Species Survival Plan® for western lowland gorillas. Our study included data on 697 gorillas: 257 wild-born (WB) and 440 born at zoos or related facilities in North America. We found no significant differences in the number of reproductive zoo-born (ZB) and WB females, but more WB males sired infants than their ZB counterparts. This was influenced by a skew in the number of reproductive years for WB males in the studbook. ZB males showed no difference in infants produced per reproductive year, as compared to WB males, while ZB females produced more infants per reproductive year than did WB females. Mother-reared (MR), ZB females produced more offspring and used more reproductive opportunity than hand-reared (HR) females, whereas rearing had no effect on the reproductive success of ZB males. Moreover, MR and partially hand-reared (PHR) females were more likely to become nurturing mothers themselves. © 2002 Wiley-Liss, Inc.