Feral Pigs

Domestic pigs and the Eurasian wild boar were brought over to this country in the 1500s and 1600s for food by the Spanish and English explorers and colonists; some were released into the wild.

Most of these releases were in the South, and over the years this wild boar became naturalized throughout much of the southern part of the country. The feral pig population was pretty much held in check by the large carnivores that were present at the time, but after cougar, jaguar, bear, and wolves were reduced the boar populations increased and their range began to expand.

Secondary releases of pigs that escaped from farms and shooting preserves or that were simply let out in the woods by former pet owners has also had an impact on the numbers and distribution of feral hogs in the United States. Feral pigs rooting for food. Wild pigs were brought to this country by European explorers and cause lots of damage to farmland, pets and wildlife.

Wild pigs are smart, fast, elusive, and have a ravenous appetite. The animals have a very high reproductive potential; a female can become mature after one year and have 1 to 3 litters per season with 4-8 piglets per litter. Given their reproductive capacity, scientists estimate that 70 percent of the population must be destroyed each year to keep their numbers in check.

Studies show that breeding colonies can triple in size in 18 months or less. The small newborn piglet is very prone to predation, but once they enlarge there are not a lot of natural predators they need to fear. The average life span of a feral pig in the wild is six to eight years.

Because of their reproductive capacity and lack of predators, the wild boar population has experienced a dramatic increase since the 1970s. The large increase in population combined with their ravenous appetite has made this animal a prime invasive species throughout its range. Wild pigs will root up and eat plants, seeds, tubers, eggs, corn, soybeans, potatoes and other agricultural crops and will also kill small animals and some livestock.

Large feral pig populations can impact ground nesting birds and other animals such as turkey, quail, turtles, frogs etc. The hogs can destroy young trees and other understory vegetation in the forest and cause stream and wetland degradation by their digging and wallowing activity. A 1990 census of the feral pig population in the United States estimated that there were 2 million feral pigs found in 20 states.

A recent 2013 census lists 6 million feral pigs found in 38 states. Texas has the largest feral pig population, estimated to number 2.3 million animals. At present there are significant feral pig populations in Virginia, West Virginia, and Pennsylvania, but there are no known breeding populations in either Maryland or Delaware.

Recent estimates in Pennsylvania list 6,000 feral pigs in the state; the state has declared an open season on them, creating the Pennsylvania Feral Swine Task Force to develop strategies to control these populations. Some feral pigs have been shot in Allegany County. They more than likely migrated south from Bedford or Somerset County, Pennsylvania. Since the Potomac River separates Maryland from Virginia and West Virginia it is more likely that these invaders will arrive from the north.

The peccary is a native pig-like animal found in the Southwest U.S., Mexico, Central and South America. The peccary has a musk gland that gives it an unpleasant odor; this animal is often referred to as a skunk pig. Peccary can thrive in a number of habitats but are most often found in the desert. Development pressure in the Southwest particularly around Tucson has shrunk peccary habitat and caused them to search for food in residential areas where they feast on crops, gardens, and landscape ornamentals. The peccary, a pig-like animal, is native to the Southwest U.S., but development pressure around Tucson, Ariz., has caused its habitat to shrink.

Nature Notes for 1/11/2015