SPRING VALLEY, Wis. - Since the discovery of white-nose syndrome on U.S. soil back in 2006 nearly seven million bats have died and that has incredible implications for all of us.
In Spring Valley, Wisconsin hundreds of bats are just finishing up a season of hibernation in Crystal Cave.
Crystal Cave is home to at least 700 bats.
It's where they rest until spring comes and then they take flight to do their bat work.
Some eat 3-thousand mosquitoes a night and they are farm hands like no other.
"They eat a lot of crop pests like corn boars and other crop pests so they are important for farmers and for everybody," Crystal Cave owner Eric McMaster said.
And now the bat killer has been traced to a private mine in Grant County,Wisconsin.
In other areas white nose syndrome, a fungus, has wiped out almost 100 percent of populations.
If Wisconsin loses its 250,000 bats, that state's crops fall prey to predators.
"In Wisconsin there was anywhere from 650 million to 1.5 billion dollars worth of cost benefits that bats provide on the landscape by reducing those pests that are normally attacking the crop pests," Paul White, of the Wisconsin DNR said Thursday.
The killer disease passes from bat to bat, humans can't stop it and there is no vaccine.
The fungus that attaches to the bat while it sleeps forces a bat against its body clock by telling it to wake up and go find food during the winter months.
"They fly out to search for insects outside so most of your bat mortality is found you know, out in the woods because its cold and there are no insects so they can't make it, it's pretty gruesome," McMaster said.
A bat's life span also makes this more troubling as a bat only reproduces once a year.
A life span can be 20 years so there just aren't new populations coming around quickly enough to replace the bats are dying off.