Suidae

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Suidae
Temporal range: Oligocene–Recent
Potamochoerus porcus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Suborder: Suina
Family: Suidae
Gray, 1821
Genera

Over 30 extinct genera, 6 extant,
see text.

Suidae is the biological family to which pigs belong. In addition to numerous fossil species, up to sixteen extant species are currently recognized, classified into between four and eight genera. The family includes the domestic pig, Sus scrofa domesticus or Sus domesticus, in addition to numerous species of wild pig, such as the babirusa Babyrousa babyrussa and the warthog Phacochoerus aethiopicus. All suids are native to the Old World, ranging from Asia and its islands, to Europe, and Africa.

The earliest fossil suids date from the Oligocene epoch of Asia, and their descendants reached Europe during the Miocene.[1] Several fossil species are known, and show adaptations to a wide range of different diets, from strict herbivory to possible carrion-eating (in Tetraconodon).[2]

Physical characteristics[edit]

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 (4–7 ft) and 130–275 kg (300–600 lb) in the Giant Forest Hog. 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.[citation needed] The males possess a corkscrew-shaped penis, which fits into a similarly shaped groove in the female's cervix.[4][5]

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: 1-3.1.2-4.33.1.2.3

Behaviour and reproduction[edit]

Wild boar feeding on carcass, Yala National Park.

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]

Classification[edit]

Bearded Pig, Sus barbatus
Chleuastochoerus fossil skull

The complete list of living species, and a partial list of extinct genera known from the fossil record, extinct taxa marked with a dagger "†",[2] are:

References[edit]

  1. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 269. ISBN 1-84028-152-9. 
  2. ^ a b Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. pp. 212–213. ISBN 0-8160-1194-X. 
  3. ^ a b c Cumming, David (1984). Macdonald, D., ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 500–503. ISBN 0-87196-871-1. 
  4. ^ Peter G. G. Jackson; Peter D. Cockcroft (2007). Handbook of Pig Medicine. Elsevier Health Sciences. ISBN 0-7020-2828-2. 
  5. ^ Virginia Douglass Hayssen; Ari Van Tienhoven (1993). Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-specific Data. Cornell University Press. ISBN 0-8014-1753-8. 
  6. ^ a b Maeva, J.O. (2009). "The differentiation of bunodont Listriodontinae (Mammalia, Suidae) of Africa: new data from Kalodirr and Moruorot, Kenya". Zoological Journal of the Linnean Society 157 (3): 653–678. doi:10.1111/j.1096-3642.2008.00525.x. 
  7. ^ a b c d e Maeva, J.O.; et al. (2010). "Phylogenetic relationships of the Suidae (Mammalia, Cetartiodactyla): new insights on the relationships within Suoidea". Zoologica Scripta 39 (4): 315–330. doi:10.1111/j.1463-6409.2010.00431.x. 
  8. ^ Funk, S.M.; et al. (2007). "The pygmy hog is a unique genus: 19th century taxonomists got it right first time round". Molecular Phylogenetics and Evolution 45 (2): 427–436. doi:10.1016/j.ympev.2007.08.007. PMID 17905601. 
  9. ^ Htike, T.; et al. (2005). "A revision of Tetraconodon (Mammalia, Artiodactyla, Suidae) from the Miocene of Myanmar and description of a new species". Paleontological Research 9 (3): 243–254. doi:10.2517/prpsj.9.243.