Southern White-cheeked Gibbon

The southern white-cheeked gibbon, scientifically Nomascus siki, inhabits central Vietnam and Laos, with a historical range extending from the Nam Theun and Rao Nay rivers in the north to the Banghiang and Thach Han rivers in the south, occupying lowland broadleaf forest and, in some populations, forested mountains. Juveniles are light brown until weaning, then turn black; adult males remain black while adult females turn brown, and males are distinguished by a large patch of white fur around the mouth rather than the cheek streaks seen in related species. Like other gibbons it is arboreal and frugivorous. It is classified as Critically Endangered, having declined by around 50 percent over 45 years due to habitat loss from logging and farming and hunting for food, traditional medicine and the pet trade.