Geissmann T., 1987: Age of sexual maturity in gibbons (Hylobates spp). International Journal of Primatology 8: 497 (Abstract only).

Age of sexual maturity in gibbons (Hylobates spp.)

T. Geissmann

Anthropological Institute, University Zürich-Irchel

From studies of both wild and captive animals, gibbons are generally thought to reach sexual maturity at about 6 to 8 years of age, and the siamang (Hylobates syndactylus) at about 8 to 9 years. However, a review of the literature reveals that, in most cases, the exact age of the maturing animals was not known and had to be estimated. This study presents four case reports on captive gibbons of known age. Captive males of the crested gibbon (H. concolor) and of the siamang (H. syndactylus) can breed at 4 and 4.5 years of age, respectively. Similarly, hybrid females (H. lar x H. moloch) can breed as early as 5.1 years of age. This finding may help to improve the breeding success of the captive gibbon population. Possible implications for the interpretation of group size regulation and the reproductive strategy of wild gibbons are discussed.