Scientists investigate the success of wild pig invasions

Oct. 10 (UPI) -- It's obvious that wild pigs, or feral hogs, are extremely successful invaders. Researchers estimate a population of between 2 and 6 million is living in North America, causing millions of dollars of damage in at least 39 states and several Canadian provinces.

Now, thanks to a new study, scientists have gained fresh insights into what makes for a successful wild pig invasion.

Researchers used landscape-scale, real-world data to analyze how the availability of crops and non-agricultural food -- grasses, acorns, mushrooms, insects, reptiles and more -- impact the movements and behavior of invading hogs.

Using GPS data from tagged wild pigs, compiled from 24 previous studies, scientists tracked the movements of pigs in relation to their surroundings. Scientists used USDA crop data to understand how agricultural resources influenced their movements.

The authors of the new study hypothesized the feral hogs would be more likely to gravitate toward crop lands when natural food resources were scarce. Scientists also predicted higher crop densities would drive higher usage by feral pigs.

The data -- detailed this week in the journal Ecological Applications -- showed the scientists' expectations were well-founded.

Scientists also hypothesized that as non-agricultural resources increased, pigs would avoid croplands. On farmland, feral hogs are more likely to meet their end. Farmers and hunters are allowed to kill and trap wild hogs without limit. Some landowners capture hogs and sell the meat for profit.

While most farmers would prefer feral hogs gone, some landowners welcome their presence.

"Managing populations is difficult because some landowners want wild pigs on their land while others don't," Sarah Chinn of University of Georgia said in a news release. "Those that have crops need to control their losses while others might want the wild pigs around for recreational hunting or even profit."

Researchers hope their latest analysis will help wildlife officials pinpoint locations where feral hog control efforts will be most effective.

"An improved understanding of foraging behavior will help managers more effectively control invasive pests in the United States and elsewhere," said Mark Wilber, a postdoctoral fellow at Colorado State University.