Hostile Presenting in Captive Gibbons

Abstract

From 1976 to 2005, we observed 100 captive gibbons (Hylobatidae) in all 4 genera at the Gibbon Conservation Center (GCC) and noted a behavior not previously thought to be part of the ethogram of gibbons-hostile presenting-in 25 of 66 individuals of Hylobates. We observed gibbon-to-gibbon hostile presenting, featuring anogenital presenting combined with agonistic behavior, only in parent-reared gibbons. When directed toward humans, the expression of the behavior varied with the displaying gibbon's rearing condition. We here describe the behavioral details of hostile presenting as expressed in captivity.