About Hylobates albibarbis Lyon, 1911
Description and life history: The Bornean white-bearded gibbon, Hylobates albibarbis, typically has grey or dark brown fur, a black face, and a white beard. Like other gibbons, it is a small, tailless ape. This species usually lives in small family groups made up of an adult male, an adult female, and their offspring. Bornean white-bearded gibbons form pair-bonding relationships and do not build nests. They move through the forest using a method of locomotion called brachiation, in which they swing from branch to branch. They have been recorded swinging up to 15 meters (49.2 feet) in a single swing and reaching speeds of 55 kilometers (34 miles) per hour. Unlike most other primates, all gibbons walk bipedally when on the ground, holding their long arms above their heads. The average lifespan of a Bornean white-bearded gibbon is 25 years. Adults grow to between 17 and 25 inches (43 to 64 cm) in length. Males weigh approximately 6.1 to 6.9 kg (13.5 to 15.2 pounds), while females weigh 5.5 to 6.4 kg (12 to 14 pounds). Females typically reach sexual maturity at around 48 months of age.
