Abstract: Black-crested gibbon (Hylobates concolor) is the least studied lesser apes. This paper presents the information on the predator--avoidance behaviour in H. concolor. We have studied black gibbons from Mar. 1990 to Jan. 1992 in Wuliang and Ailao, Yunnan Province. The main tactics of black-crested gibbons against predators is avoidance. According to the degrees approached and threatened by human, we assign the avoidance behaviour into five categories. The adult male is the principal protector against predators, and the adult female also plays an important role in protecting group, especially when the group is attacked or severely threatened by human and non-human predators. Different individual in a group has different tactics to avoid predator.

Key words: Black-crested gibbon; Hylobates concolor; Human encounter; Non-human predator; Avoidence behavior