Bilou

Kloss's gibbon, also known as the Mentawai gibbon, the bilou or dwarf siamang, is an endangered primate in the gibbon family, Hylobatidae. It is identifiable in that it is all black, resembling the siamang with its black fur, but is considerably smaller and lacks the siamang's distinctive throat pouch. Kloss's gibbon reaches a size 17 to 25 inches and weigh at most 13 pounds (5.9 kg). As is the case for all gibbons, they have long arms and no tail. Males and females are difficult to distinguish.