The Grey Bornean Gibbon, also called Mueller's Bornean Gibbon, is native to the few remaining tropical forests of northern and eastern Borneo. Much of its forest habitat has been lost.
Like all Gibbons, they are excellent climbers and acrobats. Male and female are of similar appearance, can be brown or grey and live in monogamous, socially equal pairs.
Once you have been hanging on the strap in a crowded tube train it's difficult to give up the habit.