Domestic pig

The domestic pig, Sus domesticus, also called swine or hog, is an omnivorous, even-toed, hoofed mammal kept by people on every inhabited continent. Some authorities treat it as a subspecies of the wild boar, Sus scrofa, while others, including the American Society of Mammalogists, regard it as a separate species. Archaeological and genetic evidence points to two independent domestications during the Neolithic, one in the Near East around the Tigris basin and one in China about eight thousand years ago, and pigs brought into Europe later interbred extensively with local wild boar while keeping their domesticated traits. Adults generally weigh between 140 and 300 kilograms, have a long snout strengthened by a prenasal bone, and can live to about 27 years. Pigs are raised mainly for pork, with roughly 1.5 billion produced each year, and their hides become leather; some are kept as pets. They are social, intelligent animals that root for food, build nests before giving birth, and cool themselves by wallowing in mud, and escaped animals have become damaging feral populations in many regions.