Müller's Bornean Gibbon

Müller's Bornean Gibbon (Hylobates (Hylobates) agilis), also known as the Grey Gibbon, is a primate in the Hylobatidae or gibbon family.

Unlike other gibbon species, Grey Gibbons do not show sexual dimorphism in their fur coloration. Their fur is grey or brown colored with a ring of bright fur around their face. On the head they often have a darkly colored cap. With an average weight of 5.7 kg, they rank among the smaller of the gibbons.

Müller's Bornean Gibbon is endemic to the island of Borneo, it inhabits the northern and eastern part of the island. In the southwest of the island the Agile Gibbon lives, and surprisingly their territories hardly overlap. They are diurnal rain forest dwellers that are characterized by the long arms that all gibbons have, with which they brachiate through the trees. Grey Gibbons lives together in monogamous pairs, and defend their family territory against intruders with long, loud singing, which rings out above all else early in the morning. Their diet consists primarily of fruits. Little is known about this species reproductive patterns, but it is estimate that it is similar to those of other gibbons.

There are three subspecies of this gibbon:

• Hylobates (Hylobates) muelleri muelleri
• Hylobates (Hylobates) muelleri funereus
• Hylobates (Hylobates) muelleri abbotti