The Tongue River and Cliff Dwellers caves in the Bighorn National Forest will close April 15 and remain closed through Aug. 31 to protect mother bats and their babies. Other significant caves in the forest will be open from April 16 through Oct. 14.

Registration is required to enter any caves within the Bighorn National Forest, which is done by visiting www.fs.usda.gov/bighorn, selecting recreation and then cave registration in quick links. 

“Thanks to cave protections, our visitors are reporting very positive cave experiences this year,” said Amy Ormseth, Tongue District Ranger. “Additionally, permitted cave researchers that have been visiting the Tongue River Cave for over 50 years describe an impressive reduction in litter and the return of cave-dwelling wildlife.”

The seasonal closures are based on monitoring data and a better understanding of how bats use caves in the Bighorn National Forest. After a maternity roost of Townsend’s big-eared bats was discovered in Tongue River Cave in 2019, scientists monitored bat activity during the temporary cave closure. Maternity roosts are areas essential for female bats with pups to live protected from predators and disturbances that can hinder their babies’ growth and development. Scientists did learn that few bats were utilizing Tongue River and Cliff Dwellers Caves for hibernating.

More generally, the Bureau of Land Management and the Wyoming Game and Fish Department are urging cave visitors to take precautions to avoid spreading a dangerous fungus to bat populations.

Pseudogymnoascus destructans (Pd) causes white-nose syndrome in bats and while the disease is not transmittable to humans, visitors can slow the spread by cleaning shoes and gear before and after entering the caves.

The U.S. Geological Survey’s National Wildlife Health Center tests bats annually to detect cases of Pd in confirmed hibernaculum, locations where bats spend the winter, and the disease was recently found in Wyoming for the first time.

Researchers found bats with Pd in the Shirley Mountains on BLM land in Carbon County and in Platte County on Wyoming Military Department land. The Shirley Mountain site is home to Wyoming’s largest known hibernacula, housing roughly 75 bats of five different species through the winter hibernation period. It is also a popular site for recreation, which makes preventative measures an important step to protecting these sites and the bats that they house.

While the BLM is continuing to allow access to the public cave system, “the agency encourages public visitors to follow all recommended decontamination procedures to avoid transmission of this fungus between this and any other unaffected areas,” said Timothy Novotny of the BLM’s Rawlins Field Office.

The BLM says to follow these recommendations:

• Clean your shoes and gear before and after visiting caves or other locations where bats are present to prevent the spread of the fungus to new areas.

• Don’t take gear or clothing that’s been in an area affected by white-nose syndrome to places free of the fungus.

• Check canopies, umbrellas, and other items for roosting bats before packing up. This prevents accidentally moving potentially infected bats to new areas.

• Report sick or dead bats during the winter/spring to the Game and Fish by calling 307-332-2688. Try to record the location.

• Stay out of closed caves and mines.

Anyone with specific questions about entering caves in the Bighorn National Forest can contact the Forest Supervisor’s Office and Tongue Ranger District at 307-674-2600. For tips on how to recreate responsibly, visit National Speleological Society, caves.org/committee/education, Leave No Trace lnt.org, or Tread Lightly! at treadlightly.org.