Wichita ? Unlike other states, Kansas has succeeded in culling the herds of feral hogs tromping through its rural areas.

Feral hogs have been a growing problem in the U.S., where about 5 million wild swine caused nearly $1.6 billion in damage to crops, lawns and wildlife habitat, and by introducing diseases to domestic animals last year, The Wichita Eagle reported Saturday.

The wild animals have expanded to about 40 states, which is about double from two decades ago. The hog populations and ranges have also been growing rapidly in those states.

But in Kansas the number of wild hogs is down thanks to management practices, including aerial gunning and extensive trapping. Kansas has also banned sport hunting for feral hogs since 2006, which discourages Kansans from buying wild hogs and releasing them in the state for hunting.

“A lot of other states are watching Kansas closely,” said Seth Swafford, U.S. Department of Agriculture wildlife services director for Iowa and Missouri. “We’re paying attention.”

Curran Salter, a USDA wildlife services biologist, said there were about 2,500 feral hogs in Kansas about six years ago, and now the state has about 1,000 feral hogs.