A disease that has killed millions of bats in a decade has spread through caves in Northern America, but has yet to reach Montana.

The White Nose Syndrome started in New York and has been found in over half the states in the U.S. and in five Canadian provinces. The disease is spread by fungal spores, usually from bat to bat, but also can be carried into caves by people, according to Leona Rodreick of the Beaverhead-Deerlodge National Forest.

So, "Leave No Trace" signs are being installed in large and small caves in Montana, urging cavers to be careful in the caves and practice "Clean caving." Don't leave garbage behind, be aware of delicate formations and report any odd behavior of bats.

Rodreick reported that the Northern Region has been working the Northern Rocky Mountain Grotto to develop the educational signs.

Forest Service Biologist Amie Shovlain, in a press release, said, "Bat are our most important natural predators of night-flying insects, consuming mosquitoes and moths, among others ... Every year, bats save us billions of dollars in pest control simply by eating insects."