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
Wild horse cranial and metacarpal differences, indicates the presence of only two subspecies in postglacial times, the tarpan and Przewalski's horse. At present, the domesticated and wild horses are considered a single species, with the valid scientific name for the horse species being "Equus ferus." The wild tarpan subspecies is "E. f. ferus", Przewalski's horse is "E. f. przewalskii", and the domesticated horse is "E. f. caballus". The rules for the scientific naming of animal species are determined in the International Code of Zoological Nomenclature, which stipulates that the oldest available valid scientific name is used to name the species. Previously, when