Feral Pigs

Feral pigs look very similar to the domestic pig. They are medium-sized hoofed mammals with a long, pointed head and stocky build. Males and females look much alike. Wild hogs exhibit great variation in color and size. The average wild sow weighs about 110 pounds (ranging from 77 to 330 pounds) and the average wild boar weighs 130 pounds (ranging from 130 to 440 pounds). Unusually large, trophy-sized feral pigs have been taken that reach three feet tall, six feet long and over 500 pounds. Their hair is coarse with long bristles (coarser, denser and longer than that of a domestic pig). Colors and patterns range from solid black, gray, brown, blonde, white, or red to spotted and belted combinations of these same colors. Most generally, however, the animals are black. An adult develops a thick, scruffy mane with stiff bristles tipped with blonde.

Feral pigs have elongated, flexible, tough, flattened snouts. Their pointed ears stand erect, about four to five inches above their head, though sometimes they flop outward. Their moderately long tails are sparsely haired, straight and never coiled like the tail of a domestic pig. They have four cloven feet, similar in appearance to a deer's hooves. Boars have four continually growing tusks that can be extremely sharp. The upper tusks are often 3 to 5 inches long, but have sometimes been recorded at 9 inches in length. These upper canines curl up and out along the sides of the mouth. The shorter lower canines also turn out and curve back toward the eyes. Usually the tusks are broken or worn from use. The boars use their tusks for defense and to establish a dominance hierarchy during breeding. Due to the injuries inflicted by these tusks, boars have also developed a thick, tough skin of cartilage and scar tissue around their shoulders.

Tracks of feral pigs look similar to deer tracks, although the overall shape of a feral pig's track is rounder and less heart-shaped than that of a white-tailed deer. Pig tracks also tend to be relatively shorter (about 2 1/2 inches long), more splayed and more blunt at the tip than deer tracks. The front dewclaws, in soft soil, leave crescent shaped prints outside and behind the larger hoofs. The hind dewclaw prints, if present, look like dots.

Scat is another sign that can be used to determine if feral pigs have been in the area. The droppings may be masses of pellets or in strings of sausage-like segments. Depending on the diet of the animal, the scats can range in size and consistency from that of a dog or a horse to that of a person.

Rooting is another common sign used to identify feral pig activity. These areas can be large, covering an entire field. In soft soils, rooting can be three feet deep.

Wallows are fairly sure signs of feral pig activity in wet soils.

Feral pigs also rub on a variety of objects to scratch themselves or to remove dried mud or parasites from their skin. They have been known to rub on trees, rocks, fence posts and power poles. The rubs are usually from ground level up to about 3 feet high, usually with bits of hair or mud clinging to the rubbed object.

The home territory of a feral pig covers an area about 10 square miles or less. However, if food is in short supply, the pigs may range up to 50 square miles. They nest and rest in dense vegetation and secluded thickets. Their nests and beds are small, grass-lined hollows made of piles of grass and twigs.

A feral pig has a very strong sense of smell. It uses its tough, flexible nose to sniff out roots, tubers, and small animals living underground. Pigs also have a good sense of hearing, but a poor sense of eyesight. Feral pigs communicate with each other by grunting and squealing, similar to their domestic relatives.

These hoofed mammals can run up to 30 miles per hour and are good swimmers. They usually trot from one feeding ground to another and then slow to a walk.

Feral pigs live from about 15 to 25 years. Boars usually lead solitary lives, though several may band together. Sows forage with their young, usually about six in a family group. Several family groups may join together to live in a sounder (the proper term for a large group of pigs) of 50 or more individuals.

Feral pigs, similar to people, can mate any time of the year. If a sow is not bred during the two or three days she is in estrus (in heat), she will become sexually receptive again 21 days later. Generally pigs mate during two peak breeding seasons: one in winter (December through February) and another in early summer. When a sow is in heat, boars gather and fight for dominance slashing their sharp tusks at a rival's shoulders. Boars travel between family groups in search of receptive sows. The dominant male mates first. The less dominant males slip in and mate after the dominant boar is finished breeding.

Sexual maturity and reproductive ability of feral pigs greatly depend upon nutrition and habitat. Under optimal conditions, sows can begin breeding at 6 months of age, and produce up to 4 litters per year with each litter consisting of 4 to 12 piglets. In northern portions of their range, biologists report that reproductively active sows generally only produce 2 litters per year consisting of 4-8 piglets.

After about a 115 day gestation period, sows give birth to piglets that weigh from one to two pounds at birth. The little ones have pale stripes running the length of their body until they are six weeks old. After one week of suckling, the piglets are able to follow their mother around. The young grow rapidly and are weaned in about three months. The offspring disperse after a year with their mother and are usually sexually mature by a year and a half. The young reach adult stature within three years and are fully-grown in five to six years.

Feral pigs have the unfortunate habit of trampling down and rooting up large areas of vegetation. As mentioned above, they will scratch and dig in wet ground to form wallows. Feral pigs make these wallows to escape heat and insects. They use these wallows mostly in the hot, insect-infested summer months.

Unlike some other hoofed animals, the feral pig has a simple stomach and does not chew cud. Feral pigs are opportunistic omnivores that eat whatever plants or animals happen their way. They especially relish acorns as well as hickory and beech nuts in the autumn. At other times of the year they eat forbs, grasses, leaves, berries and other fruits, roots and tubers, corn and other agricultural crops, insects, crayfish, frogs, salamanders, snakes, mice, eggs of ground-nesting birds, young rabbits, fawns and young livestock, such as lambs, calves, kids. They can also kill larger livestock that are weak from illness or injury. When fresh meat is not available, feral pigs will also readily scavenge carrion.

Pigs feed most heavily at dawn and dusk, spending the majority of the day either wallowing in mud holes or resting in dense vegetation.

Feral pigs are fierce fighters, as their tusks, tough hide and shoulder capes attest. Although biologists in other parts of the United States report that mountain lions, bobcats and black bears occasionally prey on young feral pigs, it is highly unlikely that Wisconsin's native predators would have a very big impact on an exotic animal with a high reproductive potential.

Domestic pigs were introduced from Europe to the Americas by Spanish explorers. Over time, some pigs escaped or were intentionally released into the wild. Subsequently, free-ranging, feral populations established themselves on American soil.

In 1893, 50 feral pigs from Germany's Black Forest were released on a hunting preserve in New Hampshire's Blue Mountains. Later, in 1910 and 1912, Russian wild boars were released on a North Carolina preserve near the Tennessee border. Russian wild boars were released again in 1925 near Monterey, California and a few years later on Santa Cruz Island. Some of these transplants escaped from the hunting preserves. Many of their offspring bred with feral descendants of domestic pigs.

Today, feral pigs and hybrids of the Russian wild boars are found in 23 states with the possibility of yet-undiscovered populations in several more states. The largest populations are in the coastal states surrounding the Gulf of Mexico and California (not surprising, since Spanish explorers settled these territories). Feral pigs are found chiefly in western North Carolina, eastern Tennessee, West Virginia and, in California, on Santa Cruz Island and Monterey and San Luis Obispo counties. Small numbers of pigs are found in New Hampshire, Pennsylvania and Vermont, Alabama, Arizona, Arkansas, Georgia, Florida, Louisiana, Oklahoma, Oregon, South Carolina and Texas.

In locations where feral pigs have more recently been discovered it is likely that these "run-wild" individuals are the result of unintentional escapes from domestic swine facilities, escapes or releases from game farms, or illegal stocking. Biologists estimate the nationwide population of feral pigs to be around four million animals.

The existence of feral pigs in Wisconsin raises many issues. The DNR and most Wisconsin hunters oppose the existence and spread of feral pigs because these animals not only compete with our native white-tailed deer but they have also been associated with the local population declines of quail and wild turkey in other states.

In addition, feral pigs can transmit diseases and parasites to livestock and people. Farmers are especially worried about the potential spread of exotic diseases to their domestic livestock. Of primary concern are diseases such as pseudorabies, brucellosis and tuberculosis. Many farmers are also troubled by potential crop losses. As mentioned above, feral pigs can be extremely destructive to recently planted fields and can damage pastures, facilities and fences, resulting in serious financial losses. Wallows can affect ponds and wetlands by muddying the water, creating algae blooms, destroying aquatic vegetation and lowering overall water quality. Digging and rooting activity of feral pigs near a watercourse leads to bank erosion. All of this activity can lead to decreased livestock use and poor fish production. Officials in other countries have reported feral pigs killing lambs and other domestic stock.

Due to feral pigs' tramping and rooting behaviors, Wisconsin's and other state's wildlife biologists are becoming increasingly concerned about the devastation these exotic animals can cause to ecologically sensitive native habitats, particularly native plants and rare, threatened or endangered species. These biologists are beginning to document the population declines that feral pigs are inflicting on grassland birds, wetland wildlife, and various small mammals.

The Wisconsin Department of Natural Resources has adopted the position that feral pigs are exotic, non-native wild animals that pose significant threats to both the environment and to agricultural operations. The Department promotes aggressive removal anywhere feral pigs are reported. Feral pigs are considered unprotected wild animals with no closed season or harvest limit. Feral pigs may be removed any time throughout the year as long as those choosing to pursue them possess a valid small game license and the permission of the landowner where they intend to hunt. Also, landowners may shoot feral pigs on their own property without a hunting license, under DNR's animal nuisance control authority. The meat is reported to be of excellent quality, even considerably tastier than domestic pork. It is illegal to operate a captive feral pig hunting facility in the state of Wisconsin. It is also illegal to stock feral pigs for hunting purposes or to release hogs into the wild. Should such illegal practices be discovered in your area, contact and alert your local conservation warden immediately.