Geissmann, T. (2008). Song-diversity in a gibbon species: The silvery gibbon (Hylobates moloch) from Java (Indonesia). In Miyazaki, K., Hiraga, Y., Adachi, M., Nakajima, Y., and Tsuzaki, M. (eds.), The 10th International Conference on Music Perception and Cognition, ICMPC 10: Abstracts. 25-29 August 2008, Sapporo, Japan, Hokaido Printing Planning Co. Ltd., Sapporo, p. 30.

Song-diversity in a gibbon species: The silvery gibbon (Hylobates moloch) from Java (Indonesia)

Thomas Geissmann

Anthropological Institute, University Zürich-Irchel, Switzerland

Because male silvery gibbon songs generally exhibit a higher degree of structural variability than female songs, the syntactical rules and the degree of variability in male singing have rarely been examined. The unusual rarity of male singing in the silvery gibbon makes such a study particularly challenging. The results can be summarized as follows: (1) Males appear to exhibit individual preferences in the order of different note types used in their phrases. (2) Male phrase variability both within and between individuals appears to be higher in silvery gibbons than in most, perhaps all, other gibbon species. This high variability appears to be a derived characteristic among the Hylobatidae. I will discuss the implications of this finding for the interpretation of song function. It appears that song function cannot be identified for "the gibbon". Gibbon songs appear to be multi-functional, and the relevance of these functions appears to exhibit strong differences among gibbon species.