The Sao­la (Pseudo­ryx nghet­inhen­sis) – also known as sio­la, spindle­horn, Asian Uni­corn, or the Vu Quang bovid – is one of the world’s rarest large mam­mals, a for­est-dwelling bovine found only in the Anna­mite range of Laos and Viet­nam. Its name derives from one of the Tai lan­guages of Viet­nam and means ​“price­less, like the moon and the stars.” Dis­cov­ered in May 1992 dur­ing a joint sur­vey car­ried out by the Viet­namese Min­istry of Forestry and the World Wildlife Fund (WWF) in north-cen­tral Viet­nam, the Sao­la was the first large mam­mal new to sci­ence in the area since 1936 and one of the most spec­tac­u­lar zoo­log­i­cal dis­cov­er­ies of the 20^th century.

The Sao­la resem­bles an ante­lope, but DNA has proven it is more close­ly relat­ed to a species of cat­tle, which is why it is des­ig­nat­ed as a Pseudo­ryx, or false ante­lope.

<figcaption>Illus­tra­tion by © Eric Losh</figcaption>

It typ­i­cal­ly stands about 75 cm at the shoul­der and weighs between 80 and 100 kg. Its gen­er­al char­ac­ter­is­tics include a choco­late brown coat with a strik­ing pat­tern of white mark­ings on the head, throat and the sides of the neck; a paler shade of brown on the nape and the bel­ly; a black dor­sal stripe; and a pair of long, gen­tly curv­ing horns with sharp ends present on both sexes.

There are no Sao­las exist­ing in cap­tiv­i­ty, and sci­en­tists have cat­e­gor­i­cal­ly doc­u­ment­ed the Sao­la in the wild on only four occa­sions to date. Its small pop­u­la­tion is esti­mat­ed at between 70 and 250 and declin­ing; thus, the species is list­ed as crit­i­cal­ly endan­gered by The Inter­na­tion­al Union for Con­ser­va­tion of Nature (IUCN). The pri­ma­ry threats to the Sao­la are hunt­ing – locals con­sid­er their horns to be a prized tro­phy – and tar­get­ed off­take for the wildlife trade. They also some­times get caught in snares that have been set to catch ani­mals raid­ing crops, such as wild boar, sam­bar, and munt­jac. The Saola’s restric­tive habi­tat require­ments and aver­sion to human prox­im­i­ty are also very like­ly to endan­ger it through habi­tat loss and fragmentation.

<figcaption>Cam­era trap</figcaption>

Although insuf­fi­cient con­ser­va­tion atten­tion and resources are devot­ed to the Sao­la, the WWF con­sid­ers its rareness, dis­tinc­tive­ness and unique­ness as a pri­or­i­ty and an emblem of con­ser­va­tion in Indochi­na today.