Unlike most other members of the order, they have four hooves on each foot, although they walk only on the middle two digits, with the others staying clear of the ground. They also have a simple stomach, rather than the more complex ruminant stomach found in most other artiodactyl families.

They are small to medium animals, varying in size from 58 to 66 cm in length, and 6 to 9 kg in weight in the case of the pygmy hog, to 130 - 210 cm and 100 - 275 kg in the giant forest hog.