Babirusa actually pierce the flesh in the snout. All species of babirusa are listed as threatened by the International Union for Conservation of Nature (IUCN), shown on their Red List since at least 2010 and current in 2017. The genus is monotypic within the subfamily Babyrousinae, or alternatively considered to form a tribe, Babyrousini, of the subfamily Suinae. To date, only one fossil skull has been found to suggest a larger ancestor. All members of the genus were considered part of a single species until recently, the babirusa or pig-deer, "B. babyrussa", but following the split into several species, this scientific
Babirusa name is restricted to the Buru babirusa from Buru and the Sula Islands, whereas the best-known species, the north Sulawesi babirusa, is named "B. celebensis". The split, which uses the phylogenetic species concept, is based on differences in size, amount of hair on body and tail-tuft, and measurements of the skull and teeth. "B. babyrussa beruensis" was described as an extinct, Pleistocene subspecies from southwestern Sulawesi before babirusas were split into multiple species. Babirusa are notable for the long upper canines in the males. The upper canines of male babirusa emerge vertically from the alveolar process, penetrating though the skin