The wild hog is native to Europe, Asia, Northern Africa, Japan, and the Malayan Islands. In 1912, a shipment of European wild boar from Poland or Germany was transported to a private game preserve on Hooper Bald in western North Carolina. Hooper Bald is 15 miles southwest of the park boundary in what is now the Nantahala National Forest.
Wild Hog by Deb Campbell
Some of the wild boar escaped from the preserve and reached the park by the late 1940s. During the wild boar’s movement toward the park, interbreeding occurred with domestic pigs, the result of which was hybrid wild hogs. The wild hogs seen in the park today are descendants of these animals, even though most still carry the characteristics of the European wild boar, including black hair, long legs, and tusks. However, some of the hogs have a white blaze on their faces indicating hybridization.
Wild hogs may weigh up to 300 pounds, but most adult male hogs in the Smokies weigh about 125 pounds. Females weigh slightly less. Hogs are 3 1 ⁄2 -5 feet long and stand two to three feet at the shoulder. Both sexes have 44 teeth including a well developed set of canines. The upper tusks act as “whetstones” to sharpen the edges on the lower ones. Coat color varies from gray to black, and most piglets have longitudinal stripes until they are about four months old. Hogs have poor eyesight, but a keen sense of smell and hearing.
Piglets weigh about two pounds at birth. After three or four months, the piglets are weaned and independent of the sow. Family groups break up once the young reach sexual maturity, usually within one year. Gestation is approximately 100-125 days. The average number of young per litter is four to 12.
Reproduction depends on food supply, especially the availability of hard mast (the hard fruit from forest trees, including acorns and beechnuts). During years of mast failure, reproduction ceases, and even adults may die of starvation. The average hog has a life expectancy of about eight years. Wild hogs are the most prolific large mammal in North America.They are capable of breeding at six months, can have eight piglets per litter and produce two litters per year. One sow in the park produced 12 pigs in one litter.
The illegal release of wild hogs is becoming a national problem. Since the late 1980s, the number of states with feral or wild hog populations has increased from 19 to 38. In recent years, Great Smoky Mountains National Park has received reliable reports of individuals acquiring feral hogs from other areas and releasing them near the park.
Since 2005, about 5% of hogs tested for diseases have been positive for pseudorabies, also known as Aujeszky’s disease or “mad itch.” Prior to 2005, no hogs had tested positive for the disease. Pseudorabies does not affect people, however, it poses a potential threat to native wildlife, including mink, raccoon, foxes, coyotes, and black bears. Although natural infections of pseudorabies in non- swine hosts are not common, once infected, it is typically fatal.
Hogs migrate in search of food. They move into the cooler climate of the higher elevations during the spring and summer where the understory growth of the northern hardwood forest provides an abundance of bulbs, tubers, and wildflowers. At the end of summer, the hogs move down into the oak forests to feed on acorns and other mast. Male hogs are mainly solitary, except during the breeding season, while females and piglets gather in groups of six to ten animals.
Behavior and Damage to Park Resources
Wild hogs are usually nocturnal, but are occasionally active during the daytime. Like their domestic relatives, wild hogs will eat almost anything: flowering plants, mushrooms, snails, snakes, small mammals, bird eggs, salamanders, and carrion. But the mast crop is the mainstay of the wild hog diet.
Rooting while searching for food causes the most damage to the park. Many plant species, including ones that are rare or that take several years to flower, are eaten, trampled, or uprooted by the rototiller- like action of a foraging hog. Native animals are negatively impacted by the wild hog through direct consumption, habitat destruction, and competition for food. For example, Red-cheeked Salamanders, which are endemic to the park, are commonly eaten by hogs.
Because they have no sweat glands, hogs wallow in wet, muddy areas to keep cool and rid themselves of parasites. Wallowing damages the soil and plant life in the vicinity. Both wallowing and rooting contaminate streams, causing potential problems for native brook trout. Hog-occupied drainages have been found to have a higher concentration of coliform bacteria than unoccupied drainages. These bacteria contaminate water sources and pose a threat to human health.
The wild hog is not native to Great Smoky Mountains National Park. National Park Service policy recommends the control of non-native plant and animal species, up to and including eradication, when such species threaten resources being preserved by the park. The park has found that a combination of trapping and shooting is the most successful way to reduce the numbers of these non-native animals.
Since the invasion of the wild hog in the late 1940s, some 12,200 animals have been trapped or shot. In 1977, the park devoted personnel exclusively to wild hog control to begin a consistent removal effort. Since 1986 over 8,600 hogs have been removed. Prior to 1986, the park’s wild hog population was estimated at 2,000. The current population is estimated to be a few hundred.
There is continual monitoring of wild hogs in the park, including periodic serological surveys to track infectious diseases. Vegetation monitoring in fenced areas called “hog exclosures” gives researchers a chance to study what happens to forest succession and species populations when hogs are excluded from that particular ecosystem. Past research has included a rooting index which indicates the distribution of hogs in the park, and a bait enhancement study to determine if the hogs had a bait preference in an effort to improve trapping methods.