Wild boar (also wild pig, Sus scrofa) is a species of the pig genus Sus, part of the biological family Suidae. The species includes many subspecies. It is the wild ancestor of the domestic pig, an animal with which it freely hybridises. Wild boar are native across much of Northern and Central Europe, the Mediterranean Region (including North Africa's Atlas Mountains) and much of Asia as far south as Indonesia. Populations have also been artificially introduced in some parts of the world, most notably the Americas and Australasia; principally for hunting. Elsewhere, populations have also become established after escapes of wild boar from captivity.
The body of the wild boar is compact; the head is large, the legs relatively short. The fur consists of stiff bristles and usually finer fur. The colour usually varies from dark grey to black or brown, but there are great regional differences in colour; even whitish animals are known from central Asia. During winter the fur is much denser.
Adult boars average 120–180 cm in length and have a shoulder height of 90 cm. As a whole, their average weight is 50–90 kg kilograms (110–200 pounds), though boars show a great deal of weight variation within their geographical ranges. In central Italy their weight usually ranges from 80 to 100 kg; boars shot in Tuscany have been recorded to weigh 150 kg (331 lb). A French specimen shot in Negremont forest in Ardenne in 1999 weighed 227 kg (550 lb). Carpathian boars have been recorded to reach weights of 200 kg (441 lb), while Romanian and Russian boars can reach weights of 300 kg (661 lb). Generally speaking, native Eurasian boars follow the Bergmann's rule, with smaller boars nearer the tropics and larger, smaller-eared boars in the North of their range.
Adult males develop tusks, continuously growing teeth that protrude from the mouth, from their upper and lower canine teeth. These serve as weapons and tools. The upper tusks are bent upwards in males, and are regularly ground against the lower ones to produce sharp edges. The tusks normally measure about 6 cm (2.4 in), in exceptional cases even 12 cm (4.7 in). Females also have sharp canines, but they are smaller, and not protruding like the males' tusks.
Wild boar piglets are coloured differently from adults, having ochre, chocolate and cream coloured stripes lengthwise over their bodies. The stripes fade by the time the piglet is about 6 months old, when the animal takes on the adult's grizzled grey or brown colour (see photo in Reproduction section to compare adult and juvenile colouring). Litter size of wild boars may vary depending on their location. A study in the Great Smoky Mountains National Park in the US reported a mean litter size of 3.3. A similar study on Santa Catalina Island, California reported a mean litter size of 5. Larger litter sizes have been reported in the Middle East.
Adult males are usually solitary outside of the breeding season, but females and their offspring (both sub-adult males and females) live in groups called sounders. Sounders typically number around 20 animals, although groups of over 50 have been seen, and will consist of 2 to 3 sows; one of which will be the dominant female. Group structure changes with the coming and going of farrowing females, the migration of maturing males (usually when they reach around 20 months) and the arrival of unrelated sexually active males.
Wild boar are situationally crepuscular or nocturnal, foraging in early morning and late afternoon or at night, but resting for periods during both night and day. They are omnivorous scavengers, eating almost anything they come across, including grass, nuts, berries, carrion, roots, tubers, refuse, insects and small reptiles. Wild boar in Australia are also known to be predators of young deer and lambs.
If surprised or cornered, a boar (particularly a sow with her piglets) can and will defend itself and its young with intense vigor. The male lowers its head, charges, and then slashes upward with his tusks. The female, whose tusks are not visible, charges with her head up, mouth wide, and bites. Such attacks are not often fatal to humans, but may result in severe trauma, dismemberment, or blood loss.