VIEWING OF SELF AND NONSELF IMAGES IN A GROUP OF CAPTIVE ORANGUTANS (PONGO-PYGMAEUS-ABELLII)

Reports on self-recognition in great apes have been mostly derived fro m experimental studies of mirror behavior (mark test) requiring anesth etization of the animals. We investigated a relatively noninvasive tec hnique to study this behavior. In two experiments with a group of capt ive orangutans (1 adult male, 3 adult females, 1 juvenile male, and 1 juvenile female), we presented combinations of blank posters, life-siz e portraits of each individual in the group, a mirror, and videos. Dur ations of viewing and patterns of viewing were recorded. The prominent features of the viewing were the differences among the individuals in frequency, duration, and pattern of viewing. Some evidence of mirror- based self-referent behavior (behavior in which the activity of the an imal with its body was related to the activity of the image in the mir ror) was seen in the juvenile female, but more was seen in one adult f emale. This adult female spent the most time viewing the mirror and wa s the only animal to view her own portrait more than the other portrai ts in one session. in addition, she moved from one portrait to another , and back to the first, and to her own portrait and the mirror in a p attern resembling comparison of the two portraits as well as of her po rtrait and her mirror image. It is suggested that data based on self-r eferent behavior of the same animal during self-viewing in a mirror an d during viewing of its self-portrait and on behavior observed in the mark test are worth further investigation.