Little is known regarding the prevalence of aggression seen during introductions of captive gibbons (Hylobatidae). In this study, an online survey was developed to quantify and collect contextual details regarding the frequency and types of aggression seen during introductions of captive gibbons (Hylobatidae). Nineteen percent of institutions (17 institutions) reported observing aggression, and 6 of these institutions recorded multiple instances of aggression, though a vast majority of these cases resulted in mild injuries or none at all. The female was the primary aggressor in 23% of cases, the male was the primary aggressor in 58% of cases, and both were the primary aggressor in 1 case. Although these aggressive interactions were often not associated with a known cause, 27% of cases were associated with food displacement. In most cases, management changes, including trying new pairings, greatly reduced situational aggression, suggesting that individual personalities may play a factor in aggression. These data begin to explain the extent of aggression observed in captive gibbons; future studies will address possible correlations with aggression and introduction techniques.
