Damage and Damage Identification

Feral hog (left) and European wild boar (right). Both are the species Sus scrofa.

Wild pigs can cause a variety of damage. The most common complaint is rooting (sometimes called grubbing), resulting in the destruction of crops and pastures. Damage to farm ponds and watering holes for livestock is another common problem. Predation on domestic stock and wildlife has been a lesser problem in North America.

Figure 2. Tracks of the feral hog (left) and European wild boar (right).

Damage to crops and rangeland by wild pigs is easily identified. Rooting in wet or irrigated soil is generally quite visible, but can vary from an area of several hundred square feet (m2) or more to only a few small spots where the ground has been turned over. Rooting destroys pasture, crops, and native plants, and can cause soil erosion. Wallows are easily seen around ponds and streams. Tracks of adult hogs resemble those made by a 200-pound (90-kg) calf. Where ground is soft, dewclaws will show on adult hog tracks (Fig. 2).

Wild pig depredation on certain forest tree seedlings has been a concern of foresters in the South and West. Wild pigs have destroyed fragile plant communities in Great Smoky Mountains National Park and other preserves. They have been known to damage fences when going into gardens and can do considerable damage to a lawn or golf course in a single night.

In California, wild pigs have entered turkey pens, damaging feeders, eating the turkey feed, and allowing birds to escape through damaged fences. Wild pigs in New South Wales, Australia, reportedly killed and ate lambs on lambing grounds. Producers in Texas and California reported to USDA-APHIS-Wildlife Services that 1,473 sheep, goats, and exotic game animals were killed by wild pigs in 1991. Predation usually occurs on lambing or calving grounds, and some hogs become highly efficient predators.

Depredation to calves and lambs can be difficult to identify because these small animals may be killed and completely consumed, leaving little or no evidence to determine whether they were killed or died of other causes and then were eaten. Determining predation by wild hogs is possible if carcasses are not entirely eaten, because feral hogs follow a characteristic feeding pattern on lambs (Pavlov and Hone 1982). Photographs and additional information on wild pig predation may be found in the booklet by Wade and Bowns (1982).

Always be aware of the potential for disease transmission when feral hogs are associated with domestic livestock. Cholera, swine brucellosis, trichinosis, bovine tuberculosis, foot and mouth disease, African swine fever, and pseudorabies are all diseases that may be transmitted to livestock (Wood and Barrett 1979). Bovine tuberculosis was transmitted to beef cattle by wild hogs on the Hearst Ranch in California in 1965. Pork that was infected with hog cholera brought into Kosrae Island in the East Carolinas resulted in the decimation of all domestic and feral hogs on the island.

Legal Status

Wild pigs are game mammals in California, Texas, Tennessee, North Carolina, Puerto Rico, Hawaii, and Florida (Wood and Barrett 1979, Mayer and Brisbin 1991). In California, a depredation permit is required from the Department of Fish and Game to conduct a control program or to take depredating animals. Contact your state wildlife agency to determine if a permit is required.

Economics of Damage and Control

In most areas it is unlikely that wild pigs can be exterminated. It is theoretically possible, but the cost to do so is usually prohibitive. Landowners must generally accept the fact that they will always have some wild pigs and should therefore plan for a longterm control program.

Feral hog damage can be extensive and costly if not controlled. Control for disease suppression is extremely expensive because many hogs need to be eliminated. Crop depredations may cease after one or two hogs are shot or trapped, or intermittent hunting pres-sure is put on them. They simply move to new areas. If depredations are heavy enough to require a reduction in the overall population then a program can be very costly, depending on the size of the area involved.