What Is Killing the Bats?

Can scientists stop white-nose syndrome, a new disease that is killing bats in catastrophic numbers?

In the worst animal epidemic in years, white-nose syndrome threatens to wipe out some bat species. (Lynda Richardson)
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Like Barton and the rest of the small corps of researchers pursuing the disease, Reeder abruptly reoriented her career to deal with it. She and her students picked up the normally stately pace of science, running experiments in the field and lab as quickly as they could devise them. These days, the hallway outside her laboratory is crowded with worn backpacks and other scuffed field gear. “Sometimes I feel like a rat on an electrified grid,” she says with a laugh.

In Kentucky, Barton was also working overtime, sampling skin secretions and hair from bats in caves throughout the state. In her laboratory, she and her students cataloged naturally occurring antifungal compounds produced by bacteria and other fungi, identifying some compounds that might protect vulnerable bats from white-nose syndrome. But to test the most promising compounds, she needed something Kentucky didn’t yet have: sick bats.

When Reeder and Barton met at a bat conference in 2009, their complementary skills were obvious. “We spoke different languages, but it was clear that we needed to talk to each other,” says Reeder. Last fall, in southeastern Pennsylvania, Barton and several of Reeder’s students donned Tyvek suits and belly-crawled into the depths of one of the oldest limestone mines in North America. There, they trapped more than 100 infected bats and confined them in mesh enclosures with aerosolized antifungal compounds. They then left the bats alone to hibernate, hoping that some would survive until spring. They repeated the experiment in Reeder’s lab, applying the compounds to infected bats in her hibernation chambers.

On a mid-March afternoon, Reeder visits the four laboratory hibernation chambers that house the treated bats. The chambers, which resemble bulky refrigerators, held 128 bats last fall. Now, three of the four chambers are empty and quiet, shut down after the last of their bats died last month. In the corner of the dimly lit room, in the only operating chamber, a single bat survives—but it won’t live much longer. Through a small window, it’s possible to see its silhouette, hanging motionless from the metal rack inside. Its furry body is no larger than a human thumb.

Reeder and her students travel through the rolling Pennsylvania countryside, headed for the limestone mine where bats were caged last fall. The roadsides are dotted with gray stone houses and churches, reminders of the time when the area’s limestone provided shelter for people as well as bats. The mouth of the mine, tucked into a steep hillside above a two-lane highway, is blocked with a forbidding metal gate, designed to keep out vandals. Still, the cave is littered with beer bottles, and a message is unevenly spray-painted on the clammy rock: “This is great.”

But not for the bats in this mine, whose numbers have dropped from an estimated 10,000 two years ago to roughly 180 today. Reeder and her students zip up their Tyvek suits and pick their way through the fallen rocks on the mine floor, the beams of their headlamps cutting through the cool, misty half-dark. Little brown bats are hanging onto the rocks, alone or in twos and threes, their fur glistening with moisture. Here and there, a dead bat lies on the ground, the bodies hardly more substantial than dried leaves. The crew counts 35 live bats hanging just inside the mouth of the mine, almost half bearing visible signs of white-nose syndrome. All are far closer to the mine entrance than is normal for this time of year. Later, a few will flutter out of the mine, pale brown and reeling in the daylight.

The crew slips through a narrow horizontal slot on the side of the mine, crawling headfirst down a boulder-filled slope. There, more bad news awaits: the mesh cages have been vandalized by raccoons, and the treated bats inside have all either escaped or been eaten. An entire season of data lost—to raccoons! Among the researchers, the frustration is palpable, their reactions unprintable.

By the time she returns to the mouth of the mine, Reeder is philosophical. “I don’t do mopey very well,” she says. From her laboratory experiments, she already knows that the treatments they used can’t save bats from white-nose syndrome; at best, they may prolong their lives a little while. Perhaps different compounds, or higher concentrations of the same compounds, might boost survival rates, but those are questions for the next study.

In their search for patterns in the white-nose epidemic, Reeder and her students have found that bats in cooler conditions may have better survival rates. So it’s possible that humans could alter the temperatures in some mines—by changing the shape of entrances to direct airflow, for instance. In Tennessee, conservationists are already planning to build an artificial cave that can be kept fungus-free, and in New Hampshire, biologists are studying bats that hibernate in abandoned World War II-era bunkers, hoping that climate conditions inside will help some bats survive. The National Zoo has attempted to keep endangered Virginia big-eared bats alive in captivity, so far with limited success.

Even if such heroic measures can reduce the toll, many bat species will take generations to recover from white-nose syndrome. Thomas Kunz, a bat researcher at Boston University, is already preparing for these diminished populations. Since bats depend on each other’s body heat to warm their summer roosts, Kunz has devised artificial roosts—narrow crevices built of scrap lumber—that can be warmed efficiently by just a few bats.


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