Gabriella’s Crested Gibbons: Assessing Reproductive and Conservation Status
Gibbons are distributed across Southeast Asia from Cambodia to Laos and into China. These lesser apes are among the most endangered primate species on Earth and as such have become the focus of several flagship conservation studies. The Zoological Society of San Diego's collection holds several gibbon species that are all monogamous (a rarity in primates) and live in small family groups. The Gabriella’s crested gibbon Nomascus gabriellae has been chosen as the key species for this study as we currently have two separate family groups available for observations (held at the San Diego Zoo and the Wild Animal Park). Each family consists of a pair of sexually mature adults along with several offspring.
Gabriella’s gibbons, like other lesser ape species, are particularly vocal primates that frequently use very specific ‘duet’ calls. These vocalizations are thought to play a role in strengthening monogamous bonds and also group territoriality. This research represents a unique opportunity to record vocalizations and subsequently analyze call characteristics in relation to their behavioral context in field and managed-care settings. In doing so we will be able to assemble a vocal repertoire, or vocabulary, for this endangered species.
We also hope to ascertain levels of call variability, or the existence of dialects, by making comparisons between our family groups. We should be able to augment our findings by including additional recordings from Gabriella’s gibbons in the wild in collaboration with the CRES study of Asian leaf-eating monkeys (lead by Dr. Chia Tan). Ultimately, we wish to develop a series of “playback” techniques to observe how individuals perceive one another both in the wild and in captivity. It is hoped that such an understanding of gibbon calls will be of great use in the development of husbandry management and boosting captive breeding success in this endangered gibbon species.
