Domestic pigs (Suidae sus domestica), is a sub-species of the Suidae sus species, which also includes the wild boar. Because of their cultivation by humans, domestic pigs are the most plentiful variety of pig worldwide. Domestic pigs are intelligent and adaptable, and their ability to thrive unattended in wild conditions has led to the existence of populations of feral, or wild pigs in areas where they have either escaped from their owners or been intentionally left to breed wild. 16-th Century European explorers often left small herds of pigs on islands along their routes, knowing that they could rely on the resulting wild population for fresh meat when they returned to the area.
Pigs are omnivores, and are famed for their ability and willingness to eat or try to eat nearly anything. In the wild, they forage mainly for roots, leaves, grasses, acorns and nuts, and fruit. This generality of diet has led domestic pigs to be universally used for food waste disposal by their owners. They are primarily raised for meat and leather, and their hairs can be used as bristles, to make brushes. Because of their success as foragers and their excellent sense of smell, pigs are also used to hunt for truffles, and a few small breeds have sometimes been used as house pets, though this can become problematic, as even the smallest breeds will grow to 200+ pounds (90+ kilograms).
Pigs are well known for rolling enthusiastically in mud and dirt. They do this to cool themselves and protect their skin from the sun--pigs have no sweat glands, and are unable to cool themselves effectively by panting, as dogs do.