Simias

Simias is a monotypic genus of Old World monkeys, containing the single species known as the pig-tailed langur (Simias concolor). This large, rather heavily built monkey is endemic to several small islands off the coast of Sumatra in Indonesia, the Mentawai Islands. It has a black face, black-brown fur and a relatively short tail, only about 15 centimetres long, which makes it the only monkey of the subfamily Colobinae with a short tail. Phylogenetic analyses identify it as the sister taxon of the proboscis monkey, Nasalis larvatus. Two subspecies are recognised, Simias concolor concolor on the southern Mentawai islands of Sipora, North Pagai and South Pagai, and Simias concolor siberu on the northern island of Siberut. The animal is diurnal and arboreal and eats leaves, flowers, fruit and occasionally insects. It is heavily hunted and its populations have been declining rapidly, and the International Union for Conservation of Nature rates it as critically endangered.