Visitors at a Southern California state park have reported feeling threatened by some of the park's wildlife. But not bobcats, coyotes, rattlesnakes or any of the other usual suspects.

A herd of wild cattle has been menacing visitors at Chino Hills State Park, reports NBC Los Angeles. Some of the bovines knock down fences to get to greener pastures, but others were bred in the 14,000-acre park and have had little or no exposure to humans. Hikers, mountain bikers and campers have emailed, tweeted and posted on Facebook about several close encounters with the cows over the last two years.

Environmental groups are also concerned about the animals trampling the sensitive habitat.

With a limited budget to solve the problem, rangers have asked cowboys to lasso the cows, but this has not proven successful so far. The cattle are elusive and dozens remain hidden in the park’s corners, leaving injury or death to visitors a possibility.