They’re hungry, aggressive and can damage a pasture or field from one day to the next. That’s how wildlife experts describe the country’s booming population of feral swine.
“I’ve seen entire fields of alfalfa, peanuts, corn or other crops destroyed overnight by wild pigs,” says Justin Stevenson, a wildlife disease biologist with USDA’s Animal and Plant Health Inspection Service (APHIS) in New Mexico. “Once feral swine are introduced to an area, they will aggressively exploit its resources. They eat everything – from plant material to live animals.”
In a series of surveys sent to thousands of Texas landowners the past five years, 75% of the respondents reported pasture damage – more than any other type – from wild hogs, says Billy Higginbotham. He’s a wildlife and fisheries specialist with Texas AgriLife Extension Service.
Feral hogs in Missouri root underneath cow pies for insects and cause tremendous pasture damage, says Dan McMurtry, a USDA-APHIS wildlife biologist in Columbia, MO.
“They will put a large divot in every cow pie in a pasture,” he says. “I’ve seen pastures with over 1,000 divots. When the hogs root, the soil is elevated, creating piles that tear up rotary mower blades.”
Feral hogs also damage irrigation systems, roads, fences and water tanks. They eat young animals – including fawns, lambs and goat kids – and have been known to attack humans. “They’re capable of harboring up to 30 viral and bacterial diseases, too,” says Stevenson. “Two major ones to look out for are pseudorabies and brucellosis.”
The term “feral swine” describes descendants of Russian or European swine brought here by explorers as early as the 1500s, domestic swine that have been released or have escaped and returned to the wild or hybrids of the two.
They’ve officially been documented in 37 states. Most prevalent in the South, they’re causing big problems in other regions, too, including the Northeast and parts of the Midwest.
“Some reports estimate that economic losses from feral swine top $1.5 billion annually, but that’s a tough figure to quantify because the total number of wild hogs in the U.S. is unknown,” says Higginbotham.
Wild hogs are spreading because people transport them to many parts of the country for hunting purposes. “And that’s done without folks realizing what negative impacts the hogs will have on agriculture, native wildlife, animal and human health and safety,” says Stevenson.
Many states have implemented regulations to prohibit the transportation and/or release of feral swine. It’s legal to hunt them, but regulations vary from state to state.
No toxicants or repellents are registered for their control. Snaring, live baiting and trapping, aerial or ground shooting and hunting with dogs have been effective.
Experts favor sour corn as a bait. Cage and corral-type traps are the most commonly used designs. Baits and traps are more effective during winter or early spring because less food is available to the wild animals.
Several types of cage or corral traps can be used. The primary differences between most designs have to do with door configuration, portability and size. A remote-control camera mounted near the trap or cage is a good way to monitor activity.
To stabilize a feral hog population, 60% of it must be removed annually, says Higginbotham. For more information, visit feralhogs.tamu.edu.