Wild boars feed mostly at night. Campers near balds in the western section of the park sometimes see them or hear their grunts and snorts as they run away. The females and young travel about in family groups but the males are loners. Though the animals are elusive, spending their days resting in dense cover, the signs of their rooting are very obvious on balds, in beech gaps and open fields, and along trails in moist woods.
Wild boars move seasonally in quest of food. In spring they eat a lot of grass, as well as succulent roots and the upper parts of wildflowers, which are especially abundant in cove forests and high-elevation beech forests. In summer they continue eating grass and other herbaceous plants but also seek huckleberries, blueberries, and blackberries. When acorns, hickory nuts, beechnuts, and other tree fruits start falling, they turn their attention to these, which in abundant years can carry the boars through winter. When the mast fails they feed heavily on tubers of wild yam and the outer layer of pitch pine roots. Throughout the year they supplement this vegetable diet with whatever invertebrates, salamanders, snakes, rodents, and other small animals they can root out or catch. Carrion and garbage are always welcome, too. The wild boar, as classic an omnivore as his domestic cousin, will eat almost anything.
Aside from the competition they give other masteaters in the critical fall season, wild boars upset the ecological balance in additional ways. Susan Bratton, research biologist with the National Park Service’s Uplands Field Research Laboratory here in the Smokies, has made detailed studies of boar damage. She found that in some areas boars had greatly reduced the numbers of certain wildflowers, such as spring-beauty, yellow adder’s-tongue, and wake-robin. Many other kinds of herbaceous wildflower species in the park are known to have been eaten, uprooted, or trampled. Wild boars also damage tree roots and seedlings, but apparently avoid beeches, thus favoring the root sprouting of this species. They root up grass sod on balds, which speeds the invasion of balds by other herbaceous plants and trees and they cause soil erosion by removing the plant cover. They also harm native species by preying on those mentioned above and destroying the nests and eggs of ground-nesting birds such as grouse and turkeys.
With such a list of black marks against the non-native wild boar, it becomes readily apparent why the National Park Service is concerned about its numbers in the park. Conventional methods of trapping and directly reducing the boar population have limited their impact in certain areas of the park. Unfortunately, because of the animal’s tremendous reproductive capability the efforts are not successful in reducing the total park population. The technology to completely eradicate the boar from the park is not available at the present time. Park Service research is now aimed at control methods. Estimates of the boar population have ranged upward to 2,000. But no reliable method of counting the boar in the park has yet been devised. University of Tennessee research has indicated that there may be at least 1,000 boars in the national park. Other estimates suggest there might be twice that many. Wild boars can reproduce any month of the year and most females bear a litter of from one to twelve piglets each year. And the wild boar has few enemies in the park, although bears and bobcats may occasionally take the young boars. With such a high reproductive potential, and so few controlling agents, the wild boar population has reached a size that severely alters and damages the park’s natural environment.
Contrast these population dynamics with those of a competing native species, the black bear: Bears reproduce every other year, typically giving birth to only two cubs. When the mast fails they may not reproduce at all, apparently because the embryo does not implant, or is resorbed, or the mother has insufficient milk to keep the young alive. In some years, when bears wander out of the national park, many are killed by hunters. Each year poaching within the park takes several more. Hunting aside, bear populations became attuned to the supportive capacity of the environment through centuries of adaptation. Wild boars have been here only a few decades, far too short a time for the species to be integrated into the total forest community.
As the wild boars multiply unchecked in the park, they damage ground cover, inhibit tree reproduction, increase erosion, and decrease the native animals with which they compete for food. Perhaps hardest hit are black bears, squirrels, and those other species that in the fall depend on the all-important acorn.
Boars
The wild boar came to the Great Smoky Mountains National Park uninvited in the early 1920s. While its population remained small, the boar was not thought a menace. Since the 1960s however, it has become obvious that the boar constitutes an ecological disaster of great proportions. In feeding, the animals move together and root up the ground or a stream bed with unbelievable thoroughness.
After boars have tackled a stretch of trout stream, it looks as though a bulldozer had churned it up. Presumably they seek aquatic insects, salamanders, and even a few small fish. Salamanders are among the park’s chief biological treasures, so the boars have not endeared themselves to those who are responsible for managing wildlife here in the park.
Another biological prize in these mountains is the grass bald habitat. These energetic porkers were not slow to find balds a food source, ravenously digging for June beetle larvae. The grass bald survives only by the turf’s resistance to tree invasions, so the boar and its plowing threatens the existence of these unique, and as yet incompletely understood, grass balds that are both prizes and puzzles.
Over the years it has been suggested that diverse species are directly threatened by the expanding boar population. These include ground-nesting birds, yellow adder’s-tongue and other wildflowers, and possibly deer and bear.
Studies are underway to determine the extent of the boar’s damage, and hence the real threat they pose. But we have no good comparative figures on the populations of other species for the years before boars arrived. Despite this lack, it has not been difficult to brand the boar a villain. But to control them has not been so easy. In good years they thrive—and gobble up more park resources.
There is a food preference relationship between turkeys, deer, bear, and boars in their mutual dependence on annual acorn and hickory nut crops. The widespread chestnut blight wiped out this dependable annual crop of nuts on which bears, deer, turkeys, and other animals fed in preparation for winter before the boars arrived. Now all these species compete—and the prolific boar is a lusty competitor—for a more uncertain acorn/hickory crop.
Some would cast the boar as pure villain. Others would say that people are at fault for introducing the boar into this region as an exotic species. The sport of hunting was anticipated with relish but the consequences were not considered at all. The boars have now bred with domestic pigs to such an extent that the markings vary from animal to animal. Some show definite spots, others few or none at all. Wildlife artist George Founds, who drew the boars and bear on these pages, was once a guide in this region.
The woodlands rooting of the boars is impossible to miss at trailside. A person could not do as well with ax and hoe—or power tiller!
The wild boar is winning the contest with park efforts to control it. Fewer than 200 are trapped or killed in a year, and even these are soon replaced by the boar’s high reproductive capabilities.
Piglets are born nearly naked, so the mother builds a nest for their first week of life.