Domestic pig

Appearance

Domestic pigs typically have a large head with a long snout which is strengthened by a special prenasal bone and a disk of cartilage at the tip. The snout is used to dig into the soil to find food and is a very acute sense organ. There are four hoofed toes on each foot, with the two larger central toes bearing most of the weight, but the outer two also being used in soft ground. The dental formula of adult pigs is 3.1.4.3/3.1.4.3
, giving a total of 44 teeth. The rear teeth are adapted for crushing. In the male the canine teeth can form tusks, which grow continuously and are sharpened by constantly being ground against each other.

Most domestic pigs have rather sparse hair covering on their skin, although woolly coated breeds, such as the Mangalitsa, are raised. Due to their inability to sweat, pigs must keep cool by creating mud wallows.

Behavior

The behaviour of domestic pigs is more like that of dogs and humans, rather than cattle or sheep; in many ways, their behaviour appears to be intermediate between that of carnivores and the more highly evolved artiodactyls. Domestic pigs seek out the company of each other and often huddle to maintain physical contact, although they do not naturally form large herds. A behavioural character of domestic pigs which they share with carnivores is nest building and bed making . Pigs root out wallows or depressions and the females will build nests in which to give birth. First she digs a depression about the size of her body. She then collects twigs, grasses and leaves, and carries these in her mouth to the depression, building them into a mound. She digs in smaller, finer material to the centre of the mound using her feet. When the mound reaches the desired height, she places large branches, up to 2 metres in length, on the surface. She enters into the mound and roots around to create a depression within the gathered material. She then gives birth in a lying position, which again is different from other artiodactyls which usually give birth in a standing position.


Domestic piglets are highly precocious and within minutes, or sometimes seconds, will attempt to suckle. The piglets fight to develop a teat order as the anterior teats produce a greater quantity of milk. Once established, this teat order remains stable with each piglet tending to feed from a particular teat or group of teats.

If conditions permit, domesticated pigs feed continuously for many hours and then sleep for many hours, in contrast to ruminants which tend to feed for a short time and then sleep for a short time. Pigs are omnivores and are highly versatile in their feeding behaviour. They can survive well by scavenging on the same types of foods that humans and dogs can live on. In the wild, they are foraging animals, primarily eating leaves, grasses, roots, fruits and flowers. Domestic pigs are intelligent and can be trained to perform numerous tasks and tricks. Recently, they have enjoyed a measure of popularity as house pets, particularly the dwarf breeds.

Very rarely, either naturally, as a result of unusually aggressive behavior, or perhaps as the result of a pathological process which alters their disposition, domestic farm-based pigs have become aggressive and injured and eaten their handlers.

Food

The domestic pig is mostly used for its meat, pork. Other food products made from pigs include pork sausage , bacon, gammon, ham and pork scratchings . The head of a pig can be used to make a preserved jelly called head cheese . Liver, chitterlings, blood and other offal from pigs are also widely used for food. In some religions, such as Judaism and Islam, pork is taboo food because there are religious restrictions on the consumption of pork.

Evolution

Archaeological evidence suggests that pigs were domesticated from wild boars as early as 13,000–12,700 BC in the Near East in the Tigris Basin being managed in the wild in a way similar to the way they are managed by some modern New Guineans. Remains of pigs have been dated to earlier than 11,400 BC in Cyprus that must have been introduced from the mainland, which suggests domestication in the adjacent mainland by then. There was also a separate domestication in China which took place about 8000 years ago.

DNA evidence from sub-fossil remains of teeth and jawbones of Neolithic pigs shows that the first domestic pigs in Europe had been brought from the Near East. This stimulated the domestication of local European wild boar resulting in a third domestication event with the Near Eastern genes ceasing in European pig stock. Modern domesticated pigs have involved complex exchanges with European domesticated lines being exported in turn to the ancient Near East. Historical records indicate that Asian pigs were introduced into Europe during the 18th and early 19th centuries.

The adaptable nature and omnivorous diet of the wild boar allowed early humans to domesticate it readily. Pigs were mostly used for food, but early civilizations also used the pigs' hides for shields, bones for tools and weapons, and bristles for brushes. In India, pigs have been domesticated for a long time mostly in Goa and some rural areas for pig toilets. Though ecologically logical as well as economical pig toilets are waning in popularity as use of septic tanks and/or sewerage system is increasing in rural areas.

Pigs were brought to southeastern North America from Europe by de Soto and other early Spanish explorers. Escaped pigs became feral and caused a great deal of disruption to Native Americans cultures who had no domesticated livestock.
Domestic pigs have become feral in many other parts of the world and have caused substantial environmental damage.

With around 1 billion individuals alive at any time, the domesticated pig is one of the most numerous large mammals on the planet.

Uses

Asian pot-bellied pigs, a small type of domestic pig, have made popular house pets in the United States beginning in the latter half of the twentieth century. Domestic farmyard pigs have also been known to be kept indoors, but due to their large size and destructive tendencies, they typically need to be moved into an outdoor pen as they grow older. Most pigs have a fear of being picked up by the stomach, but will usually calm down once placed back on the floor. Pigs are rarely used as working animals. An important exception is the use of truffle pigs – ordinary pigs trained to find truffles.

Miniature pigs, also called micro or teacup pigs, which are specifically bred to be small gained in popularity in late 2009 after several mainstream press articles claimed they were a popular pet to celebrities such as Rupert Grint of Harry Potter fame. Despite claims that the pigs will remain small their whole lives, however, these pigs may eventually grow to a large size comparable to other pet pigs. There is also the royal dandies pigs, which are particularly tiny, only bigger than hand-sized. These pigs, however, are kept small due to a lack of nourishment and proper health.