“Razorback” is an old American nickname for the wild hogs that roam much of the country, the same animals also called feral swine or wild pigs. They are not a separate species. They are the same species as the farm pig, gone wild and mixed with imported wild boar.1The Wildlife Society. Genetics help combat illegal movement of feral swine Experts now rank them among the most damaging invasive animals in the U.S., with harm that reaches farms, forests, streams, and people. Arkansas, meanwhile, made the hog a proud state mascot, even though the real animal is a pest almost everywhere it lives.2Word, Image and Sound. From Idiom to Idol: The Razorback in Arkansas’ Culture and History
Where Razorback Hogs Came From
Columbus released pigs on Caribbean islands in 1493, the first recorded pigs in the Americas.3Coping with Feral Hogs. Introduction of Feral Hogs Explorers kept doing this on purpose, leaving pigs behind as a food supply for later expeditions.4Coping with Feral Hogs. Introduction of Feral Hogs Hernando de Soto brought pigs to what is now the southeastern U.S. in the 1500s.5Wild Pig Info. History Settlers let their pigs roam free to feed themselves, and many escaped. Wild herds took hold and spread.6Wild Pig Info. History
The second chapter came in the early 1900s, when Eurasian or “Russian” wild boar were released in parts of the U.S.7Wild Pig Info. History The two lines mixed, and about 97% of U.S. wild pigs today are hybrids of wild boar and domestic pigs.8The Wildlife Society. Genetics help combat illegal movement of feral swine That boar ancestry may help explain why hybrids spread so aggressively.9PubMed. Mixed ancestry from wild and domestic lineages contributes to the rapid expansion of invasive feral swine
The name fits the look. Hogs that have been wild for generations grow lean, with a high, ridged spine and bristly hair along the back, quite unlike the round shape of a farm pig.
Wild hogs usually look different from farm pigs. Wild hogs tend to have coarse dark or mottled hair rather than pink skin, longer snouts, and tusks that can curve out of the mouth. Color and size vary widely because of the mixed ancestry. Even if you never see the animal, you can spot its signs: torn-up soil, muddy wallows, and tracks near water.
Why Wild Hog Numbers Grow So Fast
Wild pigs reproduce faster than any other wild hoofed mammal in North America.10The Journal of Wildlife Management. Factors influencing pregnancy, litter size, and reproductive parameters of invasive wild pigs They give birth in every month, with more pregnancies when food is plentiful.11The Journal of Wildlife Management. Factors influencing pregnancy, litter size, and reproductive parameters of invasive wild pigs A young female can breed once she reaches about 30 kg, roughly 66 pounds.12The Journal of Wildlife Management. Factors influencing pregnancy, litter size, and reproductive parameters of invasive wild pigs An average litter holds about 5 piglets, and bigger, older sows have larger litters.13The Journal of Wildlife Management. Factors influencing pregnancy, litter size, and reproductive parameters of invasive wild pigs Even at the cold northern edge of their range, sows keep breeding year-round.14PubMed Central. Population structure and reproductive ecology of wild pigs at the northern edge of the North American invasive range Removing only some animals often leaves enough breeders to rebuild quickly.
Births alone don’t decide how many hogs end up on the land, though. Because sows give birth so readily, what matters is how many piglets live to breeding age. In harsh northern areas, few piglets survive their first year, so populations barely grow.15PubMed Central. Population structure and reproductive ecology of wild pigs at the northern edge of the North American invasive range Weather, food shortages, and predators take piglets in hard years, and in good years those losses shrink and numbers rebound. Where food is plentiful and winters are mild, most piglets can survive, which is why the same animal can be a slow-growing nuisance in one region and an explosion in another. It also means removing big breeding sows matters most for control.
How Wild Hogs Damage Land and Water
Hogs dig with their snouts to find roots, grubs, and other food. They do it most where the ground is soft and food is concentrated, such as damp soil, creek banks, and the ground under oak trees where acorns fall. A group working through an area can churn up a large patch in a single night, which is why damage often seems to appear suddenly.
Up close, rooted ground looks plowed, with sod flipped over in chunks. Bare dug soil invites weeds and washes away in rain. In forest plots, rooting left less native ground cover and fewer kinds of sensitive native plants.16The Journal of Wildlife Management. Effects of Wild Pig Disturbance on Forest Vegetation and Soils The disturbed soil lost nutrients such as magnesium, even where hog numbers were low.17The Journal of Wildlife Management. Effects of Wild Pig Disturbance on Forest Vegetation and Soils On rangeland, good grazing grasses gave way to weeds and poor forage where hogs had rooted.18Agriculture, Ecosystems and Environment. Plant community shifts caused by feral swine rooting devalue Florida rangeland
Streams suffer too. Wallowing and rooting near water tear out plants and loosen soil, clouding streams with mud and bacteria.19Texas A&M Natural Resources Institute. Wild pigs negatively impact water quality: Implications for land and watershed management Streams in hog-heavy watersheds carried about 40 times more E. coli than streams without hogs.20PubMed. Impacts of a large invasive mammal on water quality in riparian ecosystems Hog fecal bacteria showed up in 70% of samples from hog areas and none from hog-free ones.21PubMed. Impacts of a large invasive mammal on water quality in riparian ecosystems Water where hogs wallow can carry fecal germs even when it looks clear, so avoid drinking untreated water or swimming where hog sign is heavy.
The Cost to Farms and Livestock
Hogs eat crops, and they root and trample fields as well.22PubMed Central. Wild pigs, wild costs: the economic consequences of wild pig invasions in the United States Damage to U.S. grain crops alone is estimated at about $1.06 billion a year.23PubMed Central. Wild pigs, wild costs: the economic consequences of wild pig invasions in the United States Damage to other field crops adds roughly $498 million a year.24PubMed Central. Wild pigs, wild costs: the economic consequences of wild pig invasions in the United States Grain farms also spend around $257 million a year on control and lose about $137 million in property damage.25PubMed Central. Wild pigs, wild costs: the economic consequences of wild pig invasions in the United States
Farmers often don’t see the full bill. In one Texas survey, they underestimated their true hog costs by nearly three times.26Crop Protection. Towards a more comprehensive understanding of wild pig (Sus scrofa) impacts on agricultural producers: Insights from a Texas case study The hidden costs include replanting, extra fuel and time at harvest, and land lost to erosion.27Crop Protection. Towards a more comprehensive understanding of wild pig (Sus scrofa) impacts on agricultural producers: Insights from a Texas case study Damaged fences can let coyotes reach livestock. Ruts and holes slow harvest equipment and break parts. Some farmers stop planting their preferred crop where hogs are bad.
Hogs also kill animals. Wild hogs can kill young calves, lambs, goats, and poultry.28South Carolina Department of Natural Resources. Feral Hog – Damage and Diseases They can attack adult animals while they are giving birth.29USDA APHIS. Feral Swine Damage: Agriculture They are often drawn to birthing grounds, possibly by the afterbirth.30South Carolina Department of Natural Resources. Feral Hog – Damage and Diseases They kill by biting and crushing the skull or neck.31South Carolina Department of Natural Resources. Feral Hog – Damage and Diseases Keeping birthing animals close and removing afterbirth reduces the attraction, and strong fencing near birthing pens helps keep hogs out.
Wild Hogs and Native Wildlife
Wild pigs raid the nests of ground-nesting birds during nesting season.32The Journal of Wildlife Management. Opportunistic Predation of Wild Turkey Nests by Wild Pigs In one Texas study, hogs destroyed nearly 30% of wild turkey nests, as many as the top native predator.33PubMed Central. Invasive Wild Pigs as Primary Nest Predators for Wild Turkeys Hogs seem to find nests by chance while foraging, not by hunting for them.34The Journal of Wildlife Management. Opportunistic Predation of Wild Turkey Nests by Wild Pigs Even so, nest losses rise wherever many hogs and many nests overlap.35The Journal of Wildlife Management. Opportunistic Predation of Wild Turkey Nests by Wild Pigs
Diseases Wild Hogs Can Spread
Wild hogs can carry at least 30 viral and bacterial diseases and at least 37 parasites.36DigitalCommons@University of Nebraska – Lincoln. Disease Risks Associated with Increasing Feral Swine Numbers and Distribution in the United States They harbor pseudorabies, swine brucellosis, and bovine tuberculosis, which the U.S. is trying to wipe out in livestock.37PubMed Central. Feral Swine—Are They a Disease Threat to Livestock in the United States? Pseudorabies in wild hogs can reinfect domestic pig herds.38USDA APHIS. Pseudorabies
Livestock disease programs work by getting the disease out of every herd, and wild hogs are a source that farmers cannot vaccinate or test. A hog that wanders onto pasture or near a pig farm can pass a disease to farm animals through contact, shared water, or feed. One infected family group near a farm can threaten a herd that has been disease-free for years.
People who handle wild hogs face much higher risk of catching their diseases.39PubMed. Zoonotic pathogens from feral swine that pose a significant threat to public health Six hunters in Florida caught swine brucellosis from wild hogs.40PubMed Central. Wild boars as sources for infectious diseases in livestock and humans Eating wild boar meat has been linked to hepatitis E cases in Japan and trichinellosis in Canada.41PubMed Central. Wild boars as sources for infectious diseases in livestock and humans
That is why gloves matter when field dressing a hog, and why all wild pork should be cooked thoroughly.42PubMed. Zoonotic pathogens from feral swine that pose a significant threat to public health Use rubber or nitrile gloves and eye protection, avoid cutting into the reproductive organs, and handle blood carefully. Wash hands and tools well, and keep dogs from eating raw parts. Cook wild pork to well done, never rare.
Brucellosis can cause recurring fever, sweats, and joint pain weeks after exposure, and it is easy to miss. If you handle wild hogs, tell your doctor.
Why Wild Hogs Keep Spreading
Illegally trucking live hogs to new areas for hunting has driven their rapid spread over the past 40 years.43The Wildlife Society. Genetics help combat illegal movement of feral swine States with paid hunting and fenced hunting preserves were more likely to have hogs.44PubMed. Cultural and regulatory factors influence distribution and trajectory of invasive species in the United States: A wild pig case study Hogs escaping or released from holding pens created new populations in Florida.45Biological Invasions. Invasion ecology of wild pigs (Sus scrofa) in Florida, USA: the role of humans in the expansion and colonization of an invasive wild ungulate Stricter rules on moving live hogs slowed their spread.46PubMed. Cultural and regulatory factors influence distribution and trajectory of invasive species in the United States: A wild pig case study
Sport hunting can backfire. Recreational hunting can push hogs to scatter into new areas.47PubMed Central. Nuisance Wildlife in Texas: Wild Pigs After Tennessee opened statewide hog hunting in 1999, hogs spread from 6 to 70 counties by 2011.48PubMed Central. Nuisance Wildlife in Texas: Wild Pigs California made hogs a game animal in 1956, when they lived in a few coastal counties; by 1999 they were in 56 of 58.49PubMed Central. Nuisance Wildlife in Texas: Wild Pigs Hogs unused to hunting pressure may roam farther when shot at.50DigitalCommons@USU. Does Hunting Affect the Behavior of Wild Pigs?
Wild hog rules are set mainly by states, and depending on the state, either the wildlife or the agriculture agency may be in charge. Check your state’s rules before trapping, moving, or selling hogs.
How Wild Hogs Are Controlled
Hogs live in family groups of sows and young called sounders. Crews trap a whole sounder, then collar and release one hog to lead them to others.51Journal of the Southeastern Association of Fish and Wildlife Agencies. Evaluating the Factors that Impact Wild Pig Performance as Judas Pigs Collared hogs found other hogs in an average of 35 days, all within 85 days.52Journal of the Southeastern Association of Fish and Wildlife Agencies. Evaluating the Factors that Impact Wild Pig Performance as Judas Pigs Each led crews to about 10 other hogs, and females found more than males.53Journal of the Southeastern Association of Fish and Wildlife Agencies. Evaluating the Factors that Impact Wild Pig Performance as Judas Pigs
For a landowner, that points toward removing the whole group rather than shooting single hogs. Corral traps that catch the entire group work better, and pre-baiting the trap for days lets the whole family group enter before it closes. Your state wildlife agency or USDA Wildlife Services can help, and reporting sightings lets agencies track spread.
Poison baits are still developing. A sodium nitrite bait is registered for feral pigs in New Zealand, where 11 of 12 baited wild pigs died.54Journal of Pest Science. Efficacy of encapsulated sodium nitrite as a new tool for feral pig management U.S. test versions killed only about half the hogs that ate them, short of the 90% goal.55Proceedings of the Vertebrate Pest Conference. Optimization of Formulations for the Lethal Control of Feral Pigs
How the Razorback Became an Arkansas Symbol
The razorback stood for tough, clever self-reliance, but also for greed and laziness.56Word, Image and Sound. From Idiom to Idol: The Razorback in Arkansas’ Culture and History University of Arkansas students adopted the name as a badge of honor.57Word, Image and Sound. From Idiom to Idol: The Razorback in Arkansas’ Culture and History It spread to hog hats, license plates, and restaurant names across the state.58Word, Image and Sound. From Idiom to Idol: The Razorback in Arkansas’ Culture and History The mascot honors an image, not the real hog’s damage.