Suidae

Suids belong to the order Artiodactyla, and are generally regarded as the living members of that order most similar to the ancestral form. Unlike most other members of the order, they have four toes 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.[3]

They are small to medium animals, varying in size from 58 to 66 cm (23 to 26 in) in length, and 6 to 9 kg (13 to 20 lb) in weight in the case of the pygmy hog, to 130–210 cm (4.3–6.9 ft) and 100–275 kg (220–606 lb) in the giant forest hog.[4] They have large heads and short necks, with relatively small eyes and prominent ears. Their heads have a distinctive snout, ending in a disc-shaped nose. Suids typically have a bristly coat, and a short tail ending in a tassle. The males possess a corkscrew-shaped penis, which fits into a similarly shaped groove in the female's cervix.[5][6][7]

Suids have a well-developed sense of hearing, and are vocal animals, communicating with a series of grunts, squeals, and similar sounds. They also have an acute sense of smell. Many species are omnivorous, eating grass, leaves, roots, insects, worms, and even frogs or mice. Other species are more selective and purely herbivorous.[3]

Their teeth reflect their diet, and suids retain the upper incisors, which are lost in most other artiodactyls. The canine teeth are enlarged to form prominent tusks, used for rooting in moist earth or undergrowth, and in fighting. They have only a short diastema. The number of teeth varies between species, but the general dental formula is: 1–3.1.2–4.3030.1.020.3.

Wild boar feeding on carcass in Yala National Park, Sri Lanka

Suids are intelligent and adaptable animals. Adult females (sows) and their young travel in a group (sounder; see List of animal names), while adult males (boars) are either solitary, or travel in small bachelor groups. Males generally are not territorial, and come into conflict only during the mating season.

Litter size varies between one and twelve, depending on the species. The mother prepares a grass nest or similar den, which the young leave after about ten days. Suids are weaned at around three months, and become sexually mature at 18 months. In practice, however, male suids are unlikely to gain access to sows in the wild until they have reached their full physical size, at around four years of age. In all species, the male is significantly larger than the female, and possesses more prominent tusks.[3]

Bornean bearded pig (Sus barbatus)

Chleuastochoerus fossil skull

The following 18 extant species of suid are currently recognised:[8]

Image	Genus	Living Species
	Sus – pigs	Sus ahoenobarbus – Palawan bearded pig Sus barbatus – Bornean bearded pig Sus cebifrons – Visayan warty pig Sus celebensis – Sulawesi warty pig Sus oliveri – Mindoro warty pig Sus philippensis – Philippine warty pig Sus scrofa – wild boar Sus scrofa domesticus – domestic pig (sometimes treated as a full species, S. domestica) Sus verrucosus – Javan warty pig
	Porcula	Porcula salvania – pygmy hog
	Hylochoerus	Hylochoerus meinertzhageni – giant forest hog
	Potamochoerus	Potamochoerus larvatus – bushpig Potamochoerus porcus – red river hog
	Phacochoerus – warthog	Phacochoerus africanus – common warthog Phacochoerus aethiopicus – desert warthog
	Babyrousa – babirusa	Babyrousa babyrussa – Moluccan babirusa Babyrousa bolabatuensis – Bola Batu babirusa Babyrousa celebensis – North Sulawesi babirusa Babyrousa togeanensis – Togian babirusa