INDIVIDUAL AND SOCIAL-BEHAVIOR OF LOWLAND GORILLAS IN OUTDOOR EXHIBITS COMPARED WITH INDOOR HOLDING AREAS

The behavior of nine lowland gorillas (Gorilla gorilla gorilla) living in three social groups at Zoo Atlanta was compared in an indoor holdi ng area versus an outdoor exhibit. Focal animal data were collected fo r each animal during 15 min observation sessions, alternating between indoors and outdoors. A variety of solitary and social behaviors diffe red in the two conditions, All individual and social behaviors that sh owed a difference, except eating, occurred more indoors than outdoors. These included aggressive displays, reclining, self manipulation, and social examination of others, Additionally, the gorillas spent more t ime closer together in the indoor condition, A variety of other behavi ors measured did not change between the two environments, There was a clear effect on behavior of the different housing conditions in which the gorillas were kept. It is suggested that the differences in aggres sive behavior may be related to environmental complexity. It is furthe r suggested that toes should be aware that differences in behavior rep orted by caretaking staff, researchers and visitors may be a reflectio n of the differing environmental circumstances in which the animals ar e observed. (C) 1997 Elsevier Science B.V.