name = Pig
image_width = 250px
image_caption = A
sowand her piglet.
phylum = Chordata
genus = "Sus"
genus_authority = Linnaeus,
subdivision_ranks = Species
subdivision = "Sus barbatus"
Pigs, also called hogs or swine, are
ungulates which have been domesticated as sources of food, leather, and similar products since ancient times. More recently, they have been involved in biomedical research and treatments, especially for their eyes and hearts, which closely resemble those of humans. Their long association with humans has led to their considerable representation in cultural milieux from paintings to proverbs. There are 2 billion pigs on the planet. [ [http://www.fas.usda.gov/psdonline/psdQuery.aspx Production, Supply and Distribution Online Query] , United States Department of Agriculture, Foreign Agricultural Service] [ [http://www.fas.usda.gov/psdonline/psdReport.aspx?hidReportRetrievalName=Swine+Summary+Selected+Countries&hidReportRetrievalID=1649&hidReportRetrievalTemplateID=7 Swine Summary Selected Countries ] , United States Department of Agriculture, Foreign Agricultural Service, (total number is Production (Pig Crop) plus Total Beginning Stocks]
Eurasia, they are collectively grouped under the genus"Sus" within the Suidaefamily. Despite pigs' reputation for gluttony, and another reputation for dirtiness, a lesser known quality is their intelligence. The nearest living relatives of the swine family are the peccariesVerify source|date=September 2008.
Description and behavior
A pig has a snout for a nose, small eyes, and a small tail, which may be curly, kinked, or straight. It has a thick body, short legs, and coarse hair. There are four toes on each foot, with the two large middle toes used for walking.
omnivores, which means that they consume both plants and animals. Pigs will scavenge and have been known to eat any kind of food, including dead insects, worms, tree bark, rotting carcasses, garbage, and even other pigs. In the wild, they are foraging animals, primarily eating leaves, grasses, roots, fruits and flowers. Occasionally while in captivity, pigs may eat their own young if they become severely stressed.A typical pig has a large head with a long snout which is strengthened by a special bone called the prenasal bone and by a disk of cartilagein the tip.Fact|date=July 2008 The snout is used to dig into the soil to find food and is a very sensitive sense organ.
Pigs have a full set of 44
teeth. The canine teeth, called tusks, grow continually and are sharpened by the lowers and uppers rubbing against each other.
Pigs that are allowed to forage may be watched by
swineherds. Because of their foraging abilities and excellent sense of smell, they are used to find truffles in many European countries. Domesticated pigs are commonly raised as livestockby farmersfor meat(called pork), as well as for leather. Their bristly hairs are also used for brushes. Some breeds of pigs, such as the Asian pot-bellied pig, are kept as pets.
Breeding occurs throughout the year in the tropics, but births peak around rainy seasons. A female pig can become pregnant at around 8-18 months of age. She will then go into estrus every 21 days if not bred. Male pigs become sexually active at 8-10 months of age. [ The solitary adult males together and fight for the right to mate with a female. A single male usually wins control over 4 females on average. [http://animaldiversity.ummz.umich.edu/site/accounts/information/Sus_scrofa.html ADW: Sus scrofa: Information ] ] A litter of piglets typically contains between 6 and 12 piglets. After the young are weaned, two or more families may come together until the next mating season.
Pigs do not have functional
sweat glands, [ [http://www.depts.ttu.edu/porkindustryinstitute/research/MANAGING%20HEAT%20STRESS%20IN%20OUTDOOR%20PIGS.htm Managing Heat Stress In Outdoor Pigs ] ] so pigs cool themselves using water or mud during hot weather. They also use mud as a form of sunscreen to protect their skin from sunburn. Mud also provides protection against flies and parasites.
Bearded Pig("Sus barbatus") [Müller, 1838]
* Indo-chinese (or Vietnam) Warty Pig ("Sus bucculentus"). [Heude, 1892]
Visayan Warty Pig("Sus cebifrons") [Heude, 1888]
* Celebes (or Sulawesi) Warty Pig ("Sus celebensis") [Müller & Schlegel, 1843]
Flores Warty Pig("Sus heureni") [Hardjasasmita, 1987]
* Oliver's (or Mindoro) Warty Pig ("Sus oliveri") [Groves, 1997]
Philippine Warty Pig("Sus philippensis") [Nehring, 1886]
Wild Boar("Sus scrofa") [Linnaeus, 1758]
Domestic Pig("Sus scrofa domestica") [Linnaeus, 1758]
Timor Warty Pig("Sus timoriensis") [Müller & Schlegal, 1845]
Javan Warty Pig("Sus verrucosus") [Müller, 1840]
Pygmy Hogis now in the monotypicgenus "Porcula" again [Funk "et al." (2007)]
Pigs have been domesticated since ancient times in the
Old Worldand are known for their exceptional intelligence. Domestic Pigs are found across Europe, the Middle East and extend into Asia as far as Indonesia and Japan. They were brought to southeastern North America from Europe by De Soto and other early Spanish explorers. Pigs are particularly valued in China and on certain oceanic islands, where their self-sufficiency allows them to be turned loose, although the practice is not without its drawbacks (see below).
The Domestic Pig ("Sus scrofa domesticus") is usually given the scientific name "Sus scrofa", although some authors call it "S. domesticus", reserving "S. scrofa" for the Wild boar. It was domesticated approximately 5,000 to 7,000 years ago. Their coats are coarse and bristly. They are born brownish colored and tend to turn more grayish colored with age. The upper canines form sharp distinctive tusks that curve outward and upward. Compared to other artiodactyles, their head is relatively long, pointed, and free of warts. Their head and body length ranges from 900-1,800 mm and can weigh 50-350 kg.
Pigs can be trained to perform numerous simple tasks and tricks. Recently, they have enjoyed a measure of popularity as house pets, particularly the dwarf breeds.
Cultural references to pigs
Pigs are frequently referenced in culture and are a popular topic for idioms and famous quotes.
Pigs in religion
*In ancient Egypt pigs were associated with Set, the rival to the sun god
Horus. When Set fell into disfavor with the Egyptians, swineherds were forbidden to enter temples.
Hinduismthe god Vishnutook the form of a boar in order to save the earth from a demon who had dragged it to the bottom of the sea.
*In ancient Greece, a sow was an appropriate
sacrificeto Demeterand had been her favorite animal since she had been the Great Goddess of archaic times. Initiates at the Eleusinian Mysteriesbegan by sacrificing a pig.
*The pig is one of the 12-year cycle of animals which appear in the
Chinese zodiacrelated to the Chinese calendar. Believers in Chinese astrologyassociate each animal with certain personality traits. See: Pig (Zodiac).
*In keeping with Leviticus 11:7, the dietary laws of
Judaism( Kashrut, adj. Kosher) forbid, among other kinds of meat, the eating of pork in any form, considering the pig to be an unclean animal (see taboo food and drink).
*The eating of pork is also prohibited in
Islam(see Halal), among Seventh-day Adventistsand some other Christian denominations.
Catholicism, Eastern Orthodoxyand other older Christian groups, pigs are associated with Saint Anthony the Great, the patron saintof swineherds.
Domestic pigs that have escaped from farms or were allowed to forage in the wild, and in some cases wild boars which were introduced as prey for hunting, have given rise to large populations of feral pigs in North and South America, Australia, New Zealand, Hawaii and other areas where pigs are not native. Accidental or deliberate releases of pigs into countries or environments where they are an alien species have caused extensive environmental change. Their omnivorous diet, aggressive behaviour and their feeding method of rooting in the ground all combine to severely alter ecosystems unused to pigs. Pigs will even eat small animals and destroy nests of ground nesting birds. [ [http://animaldiversity.ummz.umich.edu/site/accounts/information/Sus_scrofa.html ADW: Sus scrofa: Information ] ] The
Invasive Species Specialist Grouplists feral pigs on the list of the world's 100 worst invasive speciesand says: [ [http://www.issg.org/database/species/ecology.asp?si=73&fr=1&sts=sss Ecology of Sus scrofa] , Global Invasive Species Database, The Invasive Species Specialist Group]
Pigs harbour a range of
parasites and diseases that can be transmitted to humans. These include trichinosis, " Taenia solium", cysticercosis, and brucellosis. Pigs are also known to host large concentrations of parasitic ascarid worms in their digestive tract.  The presence of these diseases and parasites is one of the reasons why pork meat should always be well cooked or cured before eating. Some religious groups that consider pork unclean refer to these issues as support for their views. 
Pigs are susceptible to
bronchitisand pneumonia. They have small lungs in relation to body size; for this reason, bronchitis or pneumonia can kill a pig quickly.
Pigs can be aggressive and pig-induced injuries are relatively common in areas where pigs are reared or where they form part of the wild or feral fauna. 
Intensive pig farming
List of pigs
List of fictional pigs
* (2007). [http://dx.doi.org/10.1016/j.ympev.2007.08.007 The pygmy hog is a unique genus: 19th century taxonomists got it right first time round] . Molecular Phylogenetics and Evolution, Volume 45, Pages 427-436
* [http://www.swinecast.com SwineCast podcast]
* [http://www.deh.gov.au/biodiversity/invasive/publications/pig/ Feral Pig Fact Sheet]
* [http://www.pigprogress.net/ Global Pig Production]
* [http://www.pbs.org/wnet/nature/pigs/index.html Nature: The Joy of Pigs - TV special on PBS]
* [http://www.pigsaspets.org/ Pigs as Pets]
* [http://www.pighealth.com/ Pig Health]
* [http://www.ncbi.nlm.nih.gov/projects/genome/guide/pig/ Pig Genome Resources]
* [http://www.biolsci.org/v3i3 Special issue on swine genome research]
* [http://www.ansi.okstate.edu/breeds/swine/ Swine Breeds, with pictures]
* [http://www.pii.ttu.edu/ University Pig Teaching and Research Program]
* [http://www.upprs.com/ United Pet Pig Registry]
Wikimedia Foundation. 2010.