A pig is any of the animals in the genus Sus, within the even-toed ungulate family Suidae. Pigs include domestic pigs and their ancestor, the common Eurasian wild boar (Sus scrofa), along with other species. Related creatures outside the genus include the peccary, the babirusa, and the warthog. Pigs, like all suids, are native to the Eurasian and African continents. Juvenile pigs are known as piglets. Pigs are highly social and intelligent animals. With around 1 billion individuals 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.