Hoolock Gibbon
This small (weighs a little over 6 kg) ape was once widespread through eastern India . They live in small monogamous family groups, consisting of a mated pair with their offspring. There are deep social bonds between group members and the group defends its territory with loud songs. Adult males are always black, with prominent white eyebrows, while adult females are gold or buff or brownish buff. They travel through trees extremely fast, descending only when forced to. Thus, clearing of the evergreen forests they live in makes them vulnerable to hunting and predation.
Also called the "bristly rabbit" because of its coarse, dark brown hair, this is one of the world's rarest mammals. Formerly found all along the foothills of the Himalayas , it faces extinction due to habitat loss, human-induced changes, being hunted for food and to protect crops, and predation by dogs.