RELEASING OR POSSESSING WILD PIGS IN KENTUCKY IS ILLEGAL!
- In Kentucky it is illegal to possess, transport, or release live, wild, feral or Eurasian pigs for any purpose (KRS 150.186).
- All captured pigs must be killed before being moved from site of capture.
- The intentional release of domestic swine also is illegal.
- The origins of many wild pig populations can unfortunately be traced to illegal releases
HELP IN THE FIGHT! - Immediately report the possession, sale, or release of wild pigs to 1-800-858-1549.
- On weekends or after hours, report to 1-800-25ALERT (1-800-252-5378).
History of Wild Pigs in Kentucky
Wild pigs (Sus scrofa) are not native to Kentucky or North America. However, their establishment in the southeastern United States dates back to the 1500’s. Early European explorers at that time brought domestic pigs with them as livestock for their settlements. The historic practices of allowing pigs to range freely and regularly releasing pigs to new areas over the following centuries encouraged the spread and establishment of wild pigs that we now see throughout the southeastern United States.
In Kentucky, reports of wild pigs were relatively uncommon until the 1990’s when sporadic reports began to emerge from the Dale Hollow Lake area of Cumberland County and the Big South Fork National River and Recreation Area in McCreary County. Today, verified sightings and documented hunter kills have confirmed that their range has expanded considerably in the Commonwealth and is no longer restricted to two localized concentrations.
Wild pigs can now be found in localized populations in all corners of the Commonwealth. The early reports of wild pigs in Cumberland and McCreary counties were most likely the result of natural range expansion from established wild pig populations in east Tennessee. Population growth from these counties into those surrounding would be expected, however, if expansion was natural. This is not the case in Kentucky, however, as the dramatic range expansion over the last decade has resulted in localized, disconnected populations across the state. Unfortunately, existing data and investigations indicate that wild pigs have colonized new areas in Kentucky via truck and trailer; the result of illegal releases for recreational hunting opportunities.
What Are Wild Pigs?
All wild or domestic pigs are descendants of Eurasian wild boar and are not native to North America. The domestication of the Eurasian wild boar occurred about 8,000 to 10,000 years ago ultimately resulting in the many varieties of domestic pigs we see today. Consequently, both domestic pigs and the Eurasian wild boar are actually the same species, Sus scrofa. Regardless of their ancestry, all pigs are an exotic, invasive species when living in Kentucky’s wilds, and they negatively impact the Commonwealth in numerous ways.
The term “wild pig” is used to describe free-ranging swine living independently of humans. Origins of such populations may be from domestic stock, Eurasian wild boar, or hybrids of these. Due to these varying ancestries wild pigs show significant variability in color, body shape, and size. Commonly, wild pigs will be blackish or brownish, but almost any color, or combination of colors, can occur. Moreover, body shape may approximate domestic varieties or range to the heavier shouldered, leaner profile of Eurasian wild boar. In Kentucky, adult pigs usually weigh between 130-200 pounds.
Wild Pig Biology
Wild pigs are extremely adaptable and can thrive in a variety of habitats. They eat almost anything, robbing our native wildlife of food and often preying on native animals as well. What’s most concerning, however, is their vigorous reproductive potential. In favorable habitat conditions, sows can breed as young as five to ten months old, and sows are capable of producing litters of 10 or more piglets twice a year! Those are frightening numbers; once wild pigs are established, they’re likely there to stay.
Habitat, Home Range and Activity Patterns
Unfortunately, wild pigs are extremely adaptable and able to thrive is most habitats in the Commonwealth. However, preferred areas are composed of dense cover for shelter and concealment and permanent water sources such as bottomland forests or riparian areas along rivers and streams. They are especially associated with these areas in hot weather because pigs do not sweat and rely on shaded bedding areas and water to stay cool. A behavior called “wallowing,” literally rolling in mud and water, allows wild pigs to stay cool while ridding themselves of biting insects. Trees near these wallows will become coated with mud as pigs rub off the mud and parasites.
The home range of a wild pig is reported to vary from a few hundred to thousands of acres. Factors influencing home range size include the availability of food, quality of the habitat, number of pigs in an area, and human disturbance. In particular, increased human activity will shift the movement of wild pigs, causing their home ranges to constrict or expand. More importantly, seasonal changes in food availability and abundance, as well as temperature influence home ranges.
Wild pigs may be active at any time of the day, numerous factors including human activity, food availability, and season may influence when they are most active. Disturbances associated with human activity, especially hunting pressure, is often sufficient to shift the movement patterns of pigs and make them nocturnal. Conversely, in times of food scarcity pigs may need to forage additional hours of the day and forage more widely regardless of other factors. Seasonally, extreme temperatures during the summer months generally results in pigs becoming nocturnal to avoid heat stress.
Food Habits
The diet of wild pigs is truly generalized and classified as “omnivorous”, which means that they can and will eat almost any organic substance that is available. As a result, wild pigs can quickly establish themselves due to their ability to adapt to almost any food source. Vegetation does dominate a pig’s diet, but animal prey is common as well.
Wild pigs primarily feed by “rooting,” where they turn over the topsoil in search of roots, tubers, invertebrates, anything edible. They use an incredible sense of smell to locate food and in addition to rooting, will graze, scavenge, and predate. Seasonal changes in their diets do occur and this greatly influences their selection of habitats. In the fall, for example, hard mast (i.e. acorns and hickory nuts) is a very common food item. Likewise, it is well documented that wild pigs consume the eggs and chicks of ground-nesting birds in the spring. Unfortunately, the feeding habits and associated behaviors of wild pigs often results in extensive damage to agriculture, ornamental plantings, and native wildlife habitats.
Collectively, much research throughout the southeastern U.S. suggests that pigs utilize food items relative to availability and encounter rather than dietary preference. It is this adaptability, coupled with continued illegal releases for hunting opportunities, that has resulted in rapidly emerging populations throughout the United States.
Social Behavior
Social groupings within wild pig populations are referred to as “sounders.” These sounders are generally comprised of related generations of adult and sub adult females and their piglets. Conversely, sub adult males may associate in smaller familial groups while mature males tend to be more solitary in nature. Generally a sounder will consist of 8 or fewer pigs that may live within a home range of only a few hundred acres. In areas consisting of higher quality habitat with abundant food availability sounders may be larger in size. By living in these sounders pig employ a safety-in-numbers strategy and are able to defend and learn as a group. Understanding this aspect of their biology is key to implementing effective population control.
Reproduction and Mortality
Wild pigs have an astounding reproductive potential compared to other large mammals. Reproduction is not seasonally driven and may occur during any time of the year with a gestation period averaging 114 days. Sows can breed as young as 6 months of age and are thereafter capable of producing 2 litters of 10 or more piglets per year, though litters more typically range from 3 to 8. While young males may also reach maturity by 6 months of age, they are commonly displaced from breeding activity by older, more dominant boars.
Survival rates across all age classes are generally high as wild pigs are very hearty animals with few predators. Pigs under about 40 pounds are most vulnerable and documented predators include coyotes, black bears, mountain lions, and alligators. In Kentucky there is little evidence to suggest significant coyote or black bear predation on wild pigs and the most significant cause of pig mortality results from human-related activities.
When all of these biological characteristics are combined, wildlife biologists and landowners are faced with a serious management dilemma. Couple the astonishing reproductive rates with limited natural mortality with good habitat conditions, and it is clear why pig populations can grow quickly.
Signs of Wild Pigs
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An Invasive Species - Understanding the Concerns
Threats generated from wild pigs are generally classified into biological, economic, and health-related concerns. Biologically, wild pigs pose serious threats as they simply outcompete native wildlife for available food and space resources. As a result, it is not uncommon for native game species such as white-tailed deer and wild turkeys to be displaced as pig numbers increase. Likewise, the destructive feeding strategy of rooting by pigs slows regeneration of seedling plant species, such as red and white oaks, which are important seasonal food items to many native game species.
Economically, threats posed by wild pigs should generate serious concern to ALL landowners. In particular, financial losses due to crop depredation by pigs will increase as pig numbers continue to grow. In western Kentucky, the KDFWR has already identified some areas in which farmers no longer plant corn due to continued damage suffered by pigs. In the Google Earth image captured below, extensive corn field damage due to pigs can be seen in a satellite image!
Google Earth captured image
Photo by Chad Soard
From a general health perspective wild pigs are one of, if not the, most active carriers of wildlife-related diseases in the U.S. Biologists have identified at least 45 different parasites and diseases that are transmissible by wild pigs and these threats extend far beyond native wildlife. In particular, wild pigs are common carriers of pseudorabies and swine brucellosis, a viral and bacterial infection that results in reproductive failure in domestic swine. As a result, the potential for just one transmission of either disease from a wild to domestic animal could have serious economic impacts on domestic swine production. Likewise, swine brucellosis is also transmissible is humans with transmission generally a result of handling the reproductive tract of an infected female. In Kentucky, the United States Department of Agriculture (USDA) has already confirmed the presence of both pseudorabies and swine brucellosis from wild pigs in Kentucky.
Photo by Dave Baker
Collectively, the biological, economical, and disease-related threats associated with wild pigs pose one of the most serious management issues in recent history for the KDFWR.