Gray bats are flourishing in a Tennessee cave thanks to one simple conservation trick

Bat populations have been on the decline in the U.S. for decades due to climate change, habitat loss and a nasty fungal disease. 

But one species has been making a major comeback in Tennessee: the gray bat. 

Gray bats are sensitive little creatures. They are about three inches long, with gray fur that turns reddish in the summer months, and live in the limestone karst of the Southeast. 

Last century, gray bat populations greatly declined as people explored caves, created dams and impoundments, or used holes in the region’s karst terrain as trash dumps. In the 1970s, the U.S. Fish and Wildlife Service listed the bat as endangered under the Endangered Species Act. (Only one other bat species, the Indiana bat, has the same listing in Tennessee.)

Gray bats are less susceptible to some modern threats like white nose syndrome, a fungal disease that has wiped out more than 90% of three types of North American bats. But the species is vulnerable to climate change and human disturbance.

“All it really takes is one person with a flashlight to go in at the wrong time of year,” said Cory Holliday, who manages Tennessee’s cave program for the Nature Conservancy. 

But gray bats also have some unique features that make it easier to protect them.

Namely, there is little habitat to safeguard: There are only about a dozen caves that house them. Other conservation efforts to protect gray bats include safeguarding the woodlands and riparian corridors near these caves. 

“They’re very social and gregarious. They form these big colonies in a small number of sites,” Holliday said, including four caves in Tennessee.

One location is the Bellamy Cave, less than an hour north of Nashville. 

In 1986, the Nature Conservancy recorded just 4,000 bats hibernating in Bellamy Cave. The group added a fence to the cave entrance at that time, and the populations started to bounce back over the next couple of decades.

In 2006, the group bought the cave and installed a more substantial, human-proof fence.

“Now, we’re consistently 350,000-plus bats,” Holliday said. “There are so many bats in there that we can’t really count them anymore.” 

In the realm of bat conservation, Holliday said it’s a rare success story.