Factors influencing the maintenance of all-male in captivity formation and gorilla groups

The social housing of males is of particular importance for captive managers of polygynous species. In this work, we highlight nine areas we believe are important to the successful formation and maintenance of all-male gorilla groups. Although more data are still needed to complete our understanding of these groups, the general picture that emerges is that all-male groups can be a functional social unit for male gorillas, the longevity of which might be improved by careful planning. It appears that the best time to form all-male groups is when the animals are still immature, as males in this age class have been observed to form some of the most stable groups. Efforts should be made to diversify the groups in terms of rearing history, particularly with respect to hand-reared males, and to limit the amount of hand rearing experienced by males. Groups probably should contain no more than three or four adult males. Exhibits should be designed to provide visual barriers, refuges for subordinate animals, the means to separate individuals, and possibly the means to isolate all-male groups from mixed-sex groups. Additionally, because it is likely that some males will have to be removed from all-male groups, zoos need to design facilities that provide state-of-the-art housing for solitary individuals. It is hoped that by identifying bachelor males early in life and establishing cooperative management plans across institutions, zoos will be able to provide beneficial, long-term social situations for all male gorillas in captivity. (C) 2004 Wiley-Liss, Inc.