Geissmann, T.; Hulftegger, A.-M. & Geyer, H. 1992: Olfactory communication in gibbons? In: Abstracts, Fourteenth Congress of the International Primatological Society, Strasbourg, France, August 16-21, 1992, p. 129, Strasbourg.

Olfactory communication in gibbons ?

T. Geissmann ¹, A.-M. Hulftegger ² & H. Geyer <sup>2

1</sup> Anthropological Institute, University Zürich-Irchel, Switzerland
² Institute of Veterinary Anatomy, Tierspital Zürich-Irchel, Switzerland

In a previous publication, the sternal gland of the siamang (Hylobates syndactylus) has been described (Geissmann, 1987: Int. J. Primatol. 8:1-15). For the present report, skin glands of virtually all gibbon species have been studied. Their macroscopic and histological characteristics are described. In the siamang, the sternal glands are particularly prominent and produce a strong scent. Distinct sternal glands also occur in H. agilis, H. lar, H. moloch, and H. muelleri. Specialized skin glands can also occur in other regions of the body. They appear to be especially important in the gibbons of the concolor group, where their secretions apparently can result in reversible changes of the fur colouration in adult females. The functions of the specialized skin glands in gibbons are poorly understood. Although they appear to play a role in olfactory communication, they are apparently not used for any kind of marking behaviour. Secretory activity increases under stress and during elevated temperatures. This suggests functional analogies to the axillary glands occurring in humans and the African apes.