Photo credit: Paul Asman & Jill Lenoble, https://flic.kr/p/4ho6Zn
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Species at a Glance
The feral hog, also known as the feral pig, feral swine, or wild boar, is a feral representative of the same species including all domestic pigs. Brought to North America from Europe and Asia as a domestic livestock, or through introductions of wild boar, the feral hog has since established wild populations that pose serious ecological, economic, and public health threats.
The feral hog exhibits a wide range of colors and sizes. The average sow weighs 35-150 kg (77-330 lbs) and the average boar weighs from 59-200 kg (130-440 lbs). The hair is coarse, with long bristles. Color ranges from solid black, gray, brown, blonde, or red to striped, spotted, or grizzled color combinations. The elongated snout is flattened at the end and is tough and flexible. Males have four tusks that grow continually and can be extremely sharp. Upper tusks can be as long as 8-13 cm (3-5 in) and are usually worn or broken from use. The feet are cloven and the tail is often straight and moderately long, with sparse hair. Signs of the feral hog can include tracks, rubbings on nearby trees, rootings, and muddy wallows. In some areas, escaped or free-ranging pigs may be legally considered feral based on their location and lack of documented ownership, rather than on physical appearance.
Not to be confused with recently escaped domestic pigs, the feral hog roams free and is not tame. Escaped, or freeranging “domestic pigs” left unattended or abandoned to roam free may quickly convert to feral condition.
The feral hog can adapt to almost any kind of habitat, from tropical coastal marshes to sub-arctic latitudes. In the Mid-Atlantic region, it prefers habitats with an abundant supply of food, water, and dense cover such as swamps, shrubby communities, riparian zones, forests, agricultural fields, and urban or suburban greenways.
Through natural population growth, illegal movement by sport hunters, and escape from domestic swine operations, the feral hog has quickly spread and established wild breeding populations. It is a prolific breeder, capable of tripling its population in 14-16 months. Females reach sexual maturity at 5-6 months of age, producing 2-3 litters per year of 4-8 piglets.
Pigs were first introduced to North America from Europe around 1539, likely as semi-domestic livestock descended from Eurasian swine. Additional introductions of wild Eurasian boars from Europe and Asia for sport hunting occurred throughout the 1800s and 1900s. Over many decades, these diverse stocks have converged to form free-ranging feral hog populations which have quickly spread across the United States. Experts estimate current numbers at over 5 million animals nationwide. As of 2016, the feral hog has been reported from every Mid-Atlantic state, though no established populations occur in Maryland.
Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.
The feral hog can be destructive to fields, fences, and other infrastructure, wetlands, and many wildlife species. Its wallows can affect ponds and wetlands, muddying the water and destroying aquatic vegetation. Its rooting behavior facilitates the invasion of noxious weeds and reduces diversity and distribution of native species. The feral hog can strip a field of crops in one night, and pose a predatory threat to ground nesting birds and other wildlife. It can also transmit diseases and parasites to wildlife, livestock, pets and humans.
Information for this species profile comes from the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016).