Undergraduate Honors Theses

Thesis Defended

Spring 2012

Document Type




First Advisor

Herbert Covert


White-handed gibbons (Hylobates lar) are currently listed as Endangered on the IUCN Red List and wild populations are rapidly declining. In Thailand, the primary threat to this species is hunting for the purpose of capturing infants for the illegal pet trade. During their time in the pet trade, gibbons may be used as a tourist attraction and photographic prop. Some are relatively well cared for while others are reared in abusive conditions with no conspecific contact. In order to determine what effects the illegal pet trade has on white-handed gibbons' behavioral health and rehabilitation prospects, I analyze the behavior of numerous individual gibbons currently housed at the Gibbon Rehabilitation Project (GRP) in Phuket, Thailand. I also analyze the behavior of reintroduced gibbons. Results show that gibbons in the pet trade exhibit a variety of abnormal behaviors that correspond to those of deprived captive and laboratory primates. Some aberrancies cannot be modified later in life and many individuals will never be released. Other aberrancies are more easily alleviated and numerous gibbon groups have been successfully reintroduced into the Khao Phra Theaw Non-Hunting Area. Some important factors to rehabilitation success are age upon arrival and a rearing environment with conspecifics. However, reintroduced gibbon behavior differs from wild gibbon behavior in ways that affect immediate safety. In order for reintroduction programs to be successful, conservation initiatives must address multiple interrelated aspects including education, law enforcement, habitat protection, and economic alternatives.