Western Hoolock Gibbon eating figs, Assam, India. Hoolocks are found in Assam in North-East India, Myanmar (Burma) and in small numbers in eastern Bangladesh and southwest China. They live in monogamous pairs, which stake out a territory and use their calls to locate family members and deter other gibbons from their territory. The species is considered endangered with their numbers falling by about 90% since the early 1970s. It’s believed there are less than 5,000 left.