All members are either Endangered or Critically endangered, including the world’s rarest ape

Previously, this genus was classified as a subgenus of Hylobates, while all individuals were classified as one species, Hylobates concolor. However, the genus currently consists of 7 species that can be found from southern China to southern Vietnam, as well as on Hainan Island.

Some species are black entirely, some have unique, light-colored cheek patches, and some are light-colored with a distinct black tuft of crown fur. They also do not have visible external tails. Their diet generally consists of fruits, buds, flowers, and leaves. They also occasionally consume insects and small animals.