Sus is the genus of wild and domestic pigs, within the even-toed ungulate family Suidae. Sus include domestic pigs (Sus domesticus) and their ancestor, the common Eurasian wild boar (Sus scrofa), along with other species. Sus species, like all suids, are native to the Eurasian and African continents, ranging from Europe to the Pacific islands. Suids other than the pig are the babirusa of Indonesia, the pygmy hog of South Asia, the warthogs of Africa, and other pig genera from Africa. The suids are a sister clade to peccaries. Juvenile pigs are known as piglets. Pigs are highly social and intelligent animals. With around 1 billion of this species alive at any time, the domestic pig is among the most populous large mammals in the world. Pigs are omnivores and can consume a wide range of food. Pigs are biologically similar to humans and are thus frequently used for human medical research. Etymology The Online Etymology Dictionary provides anecdotal evidence as well as linguistic, saying that the term derives probably from Old English *picg, found in compounds, ultimate origin unknown. Originally "young pig" (the word for adults was swine). Apparently related to Low German bigge, Dutch big ("but the phonology is difficult" -- OED). ... Another Old English word for "pig" was fearh, related to furh "furrow," from PIE *perk- "dig, furrow" (source also of Latin porc-us "pig," see pork). "This reflects a widespread IE tendency to name animals from typical attributes or activities" [Roger Lass]. Synonyms grunter, oinker are from sailors' and fishermen's euphemistic avoidance of uttering the word pig at sea, a superstition perhaps based on the fate of the Gadarene swine, who drowned. The Online Etymology Dictionary also traces the evolution of sow, the term for a female pig, through various historical languages: Old English sugu, su "female of the swine," from Proto-Germanic *su- (cognates: Old Saxon, Old High German su, German Sau, Dutch zeug, Old Norse syr), from PIE root *su- (cognates: Sanskrit sukarah "wild boar, swine;" Avestan hu "wild boar;" Greek hys "swine;" Latin sus "swine", suinus "pertaining to swine"; Old Church Slavonic svinija "swine;" Lettish sivens "young pig;" Welsh hucc, Irish suig "swine; Old Irish socc "snout, plowshare"), possibly imitative of pig noise; note that Sanskrit sukharah means "maker of (the sound) su". An adjectival form is porcine. Another adjectival form (technically for the subfamily rather than genus name) is suine (comparable to bovine,