Assessing the quality of relationships in rehabilitating lar gibbons (Hylobates lar)

Abstract

Sir, Hereby we would like to describe a small project on rehabilitation in gibbons. At the Gibbon Rehabilitation Project (GRP) Phuket, Thailand, lar gibbons (Hylobates lar) that have lived their youth as pets are being rehabilitated, with release as the final aim. Rehabilitation consists of minimizing human contact, encouraging conspecific contact, and giving appropriate food and opportunities to brachiate. After having been cages at the project for a period ranging from a few months to a few years, gibbons which are thought to have a good chance of surviving in the wild are moved to one of three islands near Phuket. As a semi-natural environment is thought to facilitate the process of rehabilitation, the islands are used as an intermediate between the cages and the wild. As a rule, only pair-bonded couples and groups of single (mostly immature) gibbons are moved to the islands. Pair-bonded couples because only they have a fair chance of surviving in the wild (Brockelman 1990); single gibbons because this allows them to choose their own partners.