Feral Pigs

From Encyclopedia of Wisconsin Environmental History
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There are many invasive species threatening Wisconsin and its wilderness areas. One less talked about species is the feral pig. When people think about pigs they probably think about relatively small, pink, curly tailed, smelly creatures that produce bacon for us to enjoy. They don't think about five hundred pound tusked behemoths that run over everything in their path and aren't afraid to fight if need be. Feralpigs.jpg

Physical appearance

The average female feral pig, called a sow, weighs between eighty and three hundred thirty pounds. the males, misleadingly called boars, weigh between one hundred and four hundred forty pounds on average. Trophy boars can weigh in excess of five hundred pounds. Unlike domesticated pigs, feral pigs have long course hair that varies wildly in color and patterns. Their feet are cloven like that of a deer. Boars do grow tusks that average between three and five inches, although tusks of nine inches are not unheard of.[1]

Difference between feral and domesticated pigs

Domesticated pigs are descended from wild boar and were domesticated around 9000 years ago in china.[2] Feral pigs are a return from the domesticated form back towards their ancestral state. This causes them to be a sort of half and half species between domesticated pigs and wild boar, and they show traits from both species.

Average tusks of a feral pig


Feral pigs establish a home range of about ten kilometers. In times of scarcity they will roam up to fifty kilometers to find food. Their homes are usually made in thickets with dense vegetation that they use to make their beds. Their bedding is made of large amounts of grass and twigs. They communicate with grunts and squeals similar to domesticated pigs. they can run at a speed of 30 miles per hour and are adept swimmers. Males usually live on their own, though they do sometimes opt to work in groups. Females also tend to live alone until they breed. Every so often several families of pigs will band together into sounders of fifty or more pigs. Feral pigs can breed at anytime, but generally they breed during the winter or early summer. The dominant male breeds first, then once he is finished the other males may breed. sexual maturity depends on nutrition and other environmental factors, but most females can begin breeding at six months of age, and can breed up to four times a year with four to twelve piglets per litter. The average number of litters, however, is two per year with four to eight piglets per litter. The young are born after about 115 days in the womb. They then suckle for about three months before they are fully weaned. They generally spend a year with their mother before dispersing and usually begin starting families of their own at a year and a half of age. Feral pigs are opportunistic omnivores. This means that they will eat almost anything that they can find. They can and will kill and eat livestock and other small animals. If the animal is sick or particularly weak the pigs will also kill those animals regardless of size. Feral pigs feed most often at dawn and dusk. the rest of the day is usually spent in mud and dense vegetation.[3]

History in the Americas

Domesticated pigs were first brought to the Americas by the Spanish. Over time some pigs escaped or were released. Once in the wild they slowly changed into the form we see today. They are found most commonly in the southern coastal states and California. Feral pigs spread well because of their ability to live almost anywhere. They do prefer to have a secluded area to live such as, woodlands, swamps, and forested mountains.[4]

Environmental impacts

In simply economic terms, feral pigs eat crops, kill livestock, and transmit several exotic diseases. They can also destroy fences, pastures, equipment, and even damage buildings. Their continuous rooting in the ground and then washing off the mud lowers the quality of the water, kills fish, destroys important water based plants, and causes algae blooms. Feral pigs also have a propensity to destroy threatened plant life in the places they inhabit.[5]

Current management strategies and future plans

There are three general methods of dealing with feral pigs, shooting, trapping, and exclusion. Hunting is the preferred method of dealing with feral pigs, however, it is not considered an effective way of controlling the population of feral pigs. This is because even if all the feral pigs there now are killed, new families will move in sooner or later. Feral pigs are considered a game animal, and can be hunted as such. All that is required for such hunts is a license and a tag, however, if feral pigs are causing damage to your property you may get a depredation permit to remove them. Trapping is just as it sounds. The animals are lured into traps made of strong materials, and then either killed or removed to a different location. Exclution is simply blocking the pigs from accessing certain land. This is usually done on a small scale with metal fences. Fences need to be continuously monitored for signs of breaches as pigs will tend to dig under them. Pigs are also very strong and can smash fences made of weaker materials. currently there are no chemicals, either lethal or repellent, that are registered for the use of removing feral pigs. There are also no approved oral contraceptives at this time. Eradication of feral pigs is possible, but is extremely costly. Some such removal efforts have had costs of $1000 per pig or more.[6]


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