The saola is one of the world's rarest large mammals found only in the Annamite Range of Vietnam and Laos. It has a chocolate brown coat with patches of white on the face, throat, and sides of the neck. There is a paler shade of brown on the neck and the belly, a black dorsal stripe, a pair of nearly parallel horns (present on both sexes).
Saola inhabit wet evergreen or deciduous forests in eastern Indochina, preferring rivers and valleys. During the winters, these animals tend to migrate down to the lowlands.
Saola are active during the day as well as at night but prefer resting during the hot midday hours. They are generally solitary creatures but may gather in groups of 2 or 3 as well as up to 6 or 7 individuals. Saola are territorial and mark their territories by opening up the flap of the maxillary gland and leaving a pungent secretion on rocks and vegetation. When not foraging saola spend considerable time grooming themselves, resting, and occasionally give out short bleats.
Very little information is available about the reproductive cycle of saola. They have a fixed mating season that lasts from late August to mid-November. Females give births to only a single calf, mainly during summer between mid-April and late June. The gestation period is thought to last about 33 weeks.
The biggest threats to saola are habitat loss and habitat fragmentation. They also suffer from local hunting and the illegal trade in furs, traditional medicines, and for use of meat in restaurants and food markets. Saola also sometimes get caught in snares that have been set to catch animals raiding crops, such as wild boar, sambar, and muntjac. More than 26,651 snares have so far been removed from saola habitats by conservation groups. Due to the scarcity, the locals place much more value on the saola than more common species. Because the people in this area are traditional hunters, their attitude about killing saola is hard to change and this makes conservation difficult.
According to the IUCN Red List, the total population size of the saola is less than 750 individuals. Currently, this species is classified as Critically Endangered (CR) on the IUCN Red List and its numbers today are decreasing.