Sus scrofa
wild boar

Of all members of the pig family, Sus scrofa occupies the largest range. They originally occurred in Europe, Asia, North Africa, and the Malay Archipelago. Included in this native range were a number of island populations, including the British Isles, Corsica, Sardinia, Japan, Sri Lanka, the Ryukyu Islands, Taiwan, Hainan, Sumatra, Java, and smaller islands of the East Indies. Sus scrofa was later introduced throughout the world as domesticated animals by humans. Currently, Sus scrofa can be found nearly everywhere, from homes to barns to boggy marshes and mountainous terrain.

(Hopf, 1979; Storer, 1992) (Nowak, 1991)

Although Sus scrofa is found in a wide variety of habitats as a result of domestication and introduction to new areas, the typical wild habitat is generally moist forests and shrublands, especially oak forests and areas where reeds are abundant. They are thought to be mainly limited by maximum winter snowfall, deep snow decreases their ability to travel and find food. They are sensitive to severe temperature changes. Sus scrofa has developed the technique of wallowing in mud or water to maintain a comfortable temperature. Wallowing also protects against sunburn and insect bites. Sus scrofa has even been known to wallow in their own urine to keep cool. Temperatures dropping below 50 degrees will cause discomfort. Conversely, Sus scrofa is prone to sunstroke in unusually warm temperature.

(Hopf, 1979; vanLoon, 1979; Storer, 1992) (Nowak, 1991)

Wild boars are covered in a scant coat of coarse, bristle-like hairs ranging from dark gray to brown. Head and body length ranges from 900 to 1800 mm, tail length is about 300 mm, and shoulder height is 550 to 1100 mm. Weight averages 50 to 350 kg, though some domestic breeds can attain weights of 450 kg. Males are generally larger than females. Wild boar have four continually growing tusks, one in each quadrant of the jaw. Females have 6 pairs of mammae.

Over the course of domestication Sus scrofa has developed varying skin colors, tail lengths, and snout shapes. Sus scrofa has varying ear shapes, ranging from small and erect to low-flapping. Sus scrofa is thought to represent the primitive condition of ungulates in that they have a comparatively simple digestive system.

(Hopf, 1979; vanLoon, 1979) (Nowak, 1991)

Wild pigs usually live to about 10 years old, although some have been recorded living as long as 27 years. Mortality in the young is high.

Wild Sus scrofa in Europe are sometimes found in large herds ('sounders') of up to 100, though a more typical size is 20 individuals. Sounders are made up of females and their young. When males reach maturity they leave the group and live mainly on their own. Sounders may travel together over a large home range, but do not migrate. Wild pigs are generally active at dusk, dawn, and at night.

(vanLoon, 1979; Hopf, 1979) (Nowak, 1991)

Home Range

Studies of feral and wild S. scrofa in South Carolina and the Santa Catalina Islands (California) indicate home ranges vary from 100 to 400 hectares. Male home ranges are larger than those of females, often twice as large. Population densities in those areas and in North Carolina and Europe range from 1 to 34 animals per square kilometer. (Nowak, 1991)

Smell is by far the most advanced of the pig's senses. A large round disk of cartilage is connected to muscle that gives the snout extra flexibility. Sus scrofa also has an advanced sense of taste. They are quick to identify unknown objects with their sense of taste. It is believed that Sus scrofa lacks good eyesight. The eyes are positioned on the sides of the head, restricting their forward vision. Pigs also vocalize, consisting mainly of grunts and squeals. (Nowak, 1991)

Sus scrofa is known for its omnivorous and sometimes indiscriminate diet. The diet includes fungi, tubers and bulbs, vegetation, grains and nuts, fruit, eggs, small vertebrates, invertebrates, carrion, and manure. Such a wide range of food sources has enabled Sus scrofa to survive in a variety of environments, from deserts to mountainous terrain.

(Hopf, 1979; Storer, 1992; Porter, 1993) (Nowak, 1991)

The primary predator of mature wild pigs are humans. Mature pigs may also fall prey to very large predators, such as bears, large cats, and crocodiles. Young pigs may be preyed on by large snakes, raptors, cats, wolves, and other large predators. Pigs are extremely aggressive and bold when threatened. They use their ever-growing, sharpened tusks and the power of their bulk to charge and injure their attackers.

In ecosystems in which pigs are native, pigs contribute to the diversity of systems by disturbing the soil - creating areas for new plant colonization, and by dispersing fruit seeds. Pigs, especially the young, are also an important source of prey for large predators. In ecosystems in which pigs are not native, they are extremely destructive, outcompeting native pigs and peccaries, damaging native vegetation, and preying on native animals.

Sus scrofa carries parasitic infections transmissible to humans through eating undercooked pork and through contact, including trichinosis, cysticercosis, and brucellosis. Both domesticated and wild pigs are also quite aggressive and a surprising number of injuries results from interactions with pigs, primarily in domestic settings.

Introduced, feral populations of Sus scrofa are responsible for tremendous environmental damage worldwide. Their broad dietary habits, extremely destructive behaviors, and aggression make them one of the most destructive introduced species across the globe. Wild pigs destroy native vegetation as they dig for food, travel in herds, and create wallows. They will eat native animals, such as ground nesting birds and their eggs. Wild pigs may also act as crop pests. (Nowak, 1991)

Pigs are an integrated part of the diets of numerous human cultures. Pigs mature faster than other domesticated ungulates, have larger litters, and can feed on human garbage, making them efficient and valuable parts of many agricultural systems. Humans have taken advantage of their acute sense of smell for a variety of tasks. For instance, they have been used to find truffles, underground fungi used in French cuisine. In ancient Egypt they were used for "treading the seed." Their hoofs created holes perfect in size and depth for planting seeds. The Egyptians exploited this ability and used Sus scrofa extensively during planting seasons. Wild pigs (boars) are also hunted for sport. Miniature breeds of domestic pig have become popular as pets.

(Hopf, 1979) (Nowak, 1991)

Sus scrofa is not threatened in general. Populations of wild pig were exterminated through hunting from large parts of their native range, including the British Isles, Scandinavia, and Egypt. Reintroduction programs in Scandinavia seem to have been successful. Native pigs of the Ryukyu Islands (S. s. riukiuanus) are considered vulnerable as a result of excessive hunting. This subspecies is endemic to these islands, not an introduced feral population. There are numerous breeds of domesticated Sus scrofa, some of which seem to be in danger of disappearing and are the focus of domestic breed conservation efforts.

(Porter, 1993) (Nowak, 1991)

A symbiotic relationship between humans and pigs may have been what initiated their domestication, occurring as early as 10,000 B.C. in Thailand. Other sources place the time and place of domestication at 4900 B.C. in China. Sus scrofa may have used early gardens and garbage piles as food sources and humans took advantage of these pigs as a food source.

Sus scrofa has provoked mixed sentiments throughout history, from reverence to fear. In medieval Europe Sus scrofa was a popular carving in stone churches. They have also been regarded as a symbol of fertility and good luck. Others have not reacted so positively to Sus scrofa. Some saw the curly tail as connected to the devil. Jewish and Muslim traditions maintain strong taboos against the consumption of pork. Such adverse reactions may have originated because of the diseases associated with uncooked pork.

Domestic pigs are considered intelligent animals, more so than dogs. Circus trainers have characterized Sus scrofa individuals as quick learners with a substantial memory. Not only can they perform repetitive circus tricks, such as jumping through hoops and walking tightropes, but they can also solve simple problems such as opening a bolted door. Ivan Pavlov, the reknowned physiologist, first used pigs to perform some of his experiments, but eventually switched to dogs for reasons of temperament. It is also believed that Sus scrofa speaks a rudimentary language composed of calls, snorts, sniffs, and whistles.

Recently, Sus scrofa has been making the transition from an outdoor animal kept in the barn to an indoor pet. Miniature breeds have become popular pets.

(Hedgepeth, 1978; Hopf, 1979; vanLoon, 1979) (Nowak, 1991)