Bats Sleep in Cave Habitat Under Mark Twain's Hometown

Indiana bats gain a new safe place in Hannibal, Mo.

Beneath a town that was once home to author Mark Twain, thousands of endangered bats roost in the caves of an abandoned limestone mine.

The caves are part of the newly established Sodalis Nature Preserve in Hannibal, Mo., where Twain was raised, and they are now a protected habitat, thanks to a special conservation designation that will keep the land free of commercial and residential development.

The preserve spans 185 acres and is almost completely forested ─ all within city limits. In the middle of all of that forest is about 40 acres of land that, until it was shuttered in the 1960s, was the site of a limestone mine. Now, the caves where men and machine once toiled house an estimated 168,000 Indiana bats, representing about one third of the entire species population.

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During remarks at a recent "BatFest" dedication ceremony honoring the park's opening, U.S. Principal Deputy Assistant Secretary for Fish, Wildlife and Parks Michael Bean reminded listeners of the importance of bats as key predators of pests such as mosquitoes.

"They're also in trouble from threats like white-nose syndrome, a fungus that has killed millions of bats, including Indiana bats, across the United States," Bean added. "Sodalis Nature Preserve - the largest hibernation site in the world for Indiana bats - represents a milestone in conservation. Not just here in Missouri, but across the 22-state range of the Indiana bat."

Indiana bats (Myotis sodalis) range across the southern and midwestern United States. Small (weighing about a quarter of an ounce), with black or dark-brown fur, the animal hibernates in the winter and in the summer takes flight at night to consume all manner of flying insects, among them mosquitoes, moths, and midges.

At night, Hannibal's protected bats get to work on their foraging.They may be small of body, just a couple of inches long, but their wings can span nearly 12 inches. Credit: Steve Orr, courtesy of The Conservation Fund

In the United States, the bats have been protected as an endangered species since 1967, when their numbers dropped sharply due to issues such as forest habitat lost to land development.

With further protection in mind, conservation officials at the Hannibal park have put in place special gates at the mine's 33 entrances. Gaps in the gates lets the bats go in and out while preventing people from entering and disturbing them.

Special gates allow entrance and exit for bats in the cave system while keeping people out. Credit: Steve Orr, courtesy of The Conservation Fund

The gates don't mean, however, that people will have no access to the bats. Students in the town will get their own special looks.

"Our school is using Sodalis Nature Preserve to teach our youngsters about bats and the importance of conservation," said Hannibal Mayor James Hark in a statement.

"Prior to the discovery of this significant population of Indiana bats hibernating in the former limestone mine, it was presumed that all Indiana bats hibernating in Missouri were located south of the Missouri River," said U.S. Fish and Wildlife Service biologist Shauna Marquardt.

"The discovery of the bats at Sodalis Nature Preserve and the service's research over the last few years have changed what was understood and assumed about Indiana bats throughout the bats' range," Marquardt said. "This new information led the U.S. Fish and Wildlife Service to consider the preservation of Sodalis Nature Preserve one of the highest priorities for bat conservation in the Midwest."

Now, with colder days and nights looming, the preserve's bats should at least be able to get a good, undisturbed winter's sleep.

Top Photo: Bats roost in a newly protected cave complex in Hannibal, Mo. Credit: Steve Orr, Courtesy of the Conservation Fund Watch Video: Why You Shouldn't Be Scared Of Vampire Bats