Wild boar have been found in North America since the 15th century when European explorers released the animals from their ships. The first known infestation occurred in the West Indies by Christopher Columbus but the mainland soon followed, as did Hawaii. Some of the boars escaped, others were released intentionally for sport hunting. Wild boar are the ancestors of domesticated pigs and that connection allows the two to mate when pigs escape and become feral. Areas such as Florida and Texas are especially hard hit by the aggressive and successful animals. These states both have extensive hunting and trapping in an attempt to control the numbers.
Scientific & Common Names
Kingdom – Animalia
Phylum – Chordata
Class – Mammalia
Order – Artiodactyla
Family – Suidae
Genus – Sus
Species – S. scrofa
Common Names – Wild boar, wild hog, feral pig, feral hog, razorback, Russian wild boar
Wild boar are among the most widely distributed of all land mammals. They are naturally found in Western Europe Asia and North Africa but are invasive in North America and the Hawaiian Islands. Like all pigs, boars are omnivores and are capable of eating almost anything, from roots and berries, to eggs and carrion. They are stocky and powerfully built, with short legs and a humped back. Their head is huge, measuring a third of the body length, with powerful muscles that allow the boar to use its head like a plow or battering ram. Their lower canine teeth form tusks, which can have an exposed length of over four inches and these continue to grow throughout their lives in males. Depending on the available food supplies, they can weigh up to 220 pounds, with males typically being about 40 pounds heavier than females.
While females can breed at six months, they usually wait until they are over a year. They can breed during any season and are capable of producing two litters of 4-13 young each year. They are quite prolific and a healthy population can double in just four months. The piglets, called squeakers for the first ten months, are completely dependent on their mother, who stays close with them for the first few weeks. Their soft brown and tan striped coat begins to darken as they become juveniles, finally losing the stripes and becoming a deep brown when they are adults.
Boars are aggressive, intelligent, and resourceful. They can adapt to nearly any conditions, providing it is not too dry or freezing. They easily live beside humans, despite some concerted efforts to eradicate them. They are very social animals, living in female dominated groups called sounders. Young males leave the sounder after about a year and they will live among other young males until they become more solitary adults.
The earliest fossils from boar were found in both Europe and Asia from the Pleistocene period. Beginning in 13,000BC, humans began to domesticate wild boar, creating most of the pig breeds that exist today.
Wild boar are considered a dangerous and invasive pest in many areas. They damage crops and compete with native species for food and territory. They can be especially damaging in the closed ecosystems of islands such as Hawaii, Galapagos, and Fiji. IUCN has them listed as least concern as they are in no danger of becoming extinct.
United States Department of Agriculture National Invasive Species Information Center
Rouhe, A., and M. Sytsma. 2007. Feral Swine Action Plan for Oregon (PDF | 1.43 MB) Portland State University Center for Lakes and Reservoirs. Prepared for the Oregon Invasive Species Council.
International Union for Conservation of Nature (IUCN)
Wild Pigs in the United States: Their History, Comparative Morphology, and Current Status by John J. Mayer, I. Lehr Brisbin Jr.
Exotic Animal Field Guide: Nonnative Hoofed Mammals in the United States by Elizabeth Cary Mungall