DeeAnn Reeder, from Orangevale, studies bat behavior and immune systems at Bucknell University in Pennsylvania, where she also teaches biology. “I’ve always viewed them as these incredibly tough, well-adapted animals that can take anything you could throw at them,” she says. “Until now.”
Across the Northeast, something is wiping out hundreds of thousands of bats. Biologists, shaken by the destruction, bring back harrowing accounts from caves where they had long studied thriving populations. They tell of tiny bodies littering the snow, of slogging through the muck of animal remains, of shoveling out layers of the dead. In three years, more than a million animals have died. Gone with them is their insect-eating prowess; one biologist has calculated those fallen bats ate nearly 700 tons of moths, beetles, mosquitoes and other bugs each year. The full impact will take years to comprehend, as the effects of losing so many bats spreads to their predators and to their prey. Those tracking the wave of deaths believe it may have rippled outward from a single cave in New York state, possibly carried there from Europe on the muddy gear of some unwitting cave enthusiast. It could reach California the same way.
As best anyone can tell, the bat deaths started slowly. They spread quietly from the suspected epicenter of Howe’s Cave, west of Albany, N.Y. By January 2008, reports began to trouble government and research biologists. In New York and Vermont, something unusual was driving bats out of hibernation before their normal time. They would collapse on the snow, emaciated, and die. A pale, whitish fungus grew on their bodies. Genetic tests are still ongoing, but the fungus appears identical to one found in Europe. There, it was seen growing harmlessly on some hibernating bats as long ago as the 1980s. Some speculate that those bats have evolved to tolerate it. Others suggest the fungus in America has mutated into some more virulent form.
The first time DeeAnn Reeder saw a faint powdering of pale fungus growing on bats’ noses in one of her own research caves, her stomach plunged. It felt as if she were going to throw up. Then it got worse.
“You would look at bats on the cave wall and know they were going to die,” Reeder said, “Just pathetic looking, horrible looking animals.” Fungus grew all across their faces. They were so thin and dehydrated that they seemed almost crispy. Some clung to the wall by only one foot.
Reeder, 40, studies bat behavior and immune systems. She is a small woman, just 5 feet 3 inches tall, with strong cheekbones and pale eyebrows that give out halfway over each eye. She grew up in Orangevale and spent her summers at a rustic cabin beside Wrights Lake, where she would spend hours watching marmots – bigger, heftier versions of the squirrels she knew at home. They ate like squirrels, sometimes sitting upright, both paws delicately clasped around a curl of pancake or a melon rind that her parents had tossed out to feed the animals.
“I was always at heart an animal behaviorist,” Reeder says now. She got her doctorate at the University of California, Davis, where she studied monkeys at the primate center. Now she teaches biology at Bucknell University in central Pennsylvania, and she has long been a co-editor of a definitive taxonomic volume, “Mammal Species of the World.”
Out of all the mammals of the world, Reeder chose the bat. “They have these amazing strategies, including hibernation, to deal with the fact that there is basically no food for half the year,” she says. She loves their ingenuity, the way they parse out reproduction, mating in the fall, then waiting until spring to develop a pregnancy. She marvels at their wings, a thin, translucent unfurling of strength and elasticity.
“I’ve always viewed them as these incredibly tough, well-adapted animals that can take anything you could throw at them,” she says. “Until now.”
When biologists first identified the fungus growing on the bodies of so many dead bats, they named it Geomyces destructans. They have not fully established whether the fungus, with its characteristic start at the nostrils of a hibernating bat, is the killer itself or is preying on bats weakened by something else. But the name, “destructans,” captures biologists’ suspicions and their desperation. Once a telltale wisp of white fungus is seen at the nostrils of a hibernating bat, it is likely that 95 percent to 100 percent of the bats hibernating with it will die. The outbreak, which researchers have come to call “white nose syndrome,” is killing off entire communities in the caves where bats gather to hibernate. Bats tend to sprawl over each other during hibernation, like sleeping puppies or kittens, and the behavior, known as clustering, is probably hastening the spread of white nose syndrome from bat to bat. At first, biologists wondered whether low food supplies or pollutants might be felling the bats. But the mystery disorder has been radiating outward from its epicenter just as a disease outbreak would. So far, it has spread across nine states, at a rate of about 200 miles each winter.
Somewhere between 45 and 48 species of bats fly across the night skies of the United States, some sipping nectar, some scooping up insects into a basketlike trap they can form with their legs. Roughly half of these bats migrate in the winter, or live in regions so warm that there is food for them year round. The rest hibernate, stretching out the meals of spring, summer and fall to last an entire year.
Bats that hibernate must balance on an energy tightrope. They have to remain light enough to fly until they are ready for torpor. Yet they must store enough fat to live on all winter. They make their fat supplies last by dramatically slowing their heart rate, their breathing rate and the rest of their metabolism. Like other small hibernating mammals, they also arouse sporadically during the winter, but each arousal exacts a high cost, burning up in hours calories that would otherwise last for weeks. Researchers don’t fully understand how white nose syndrome kills, but it’s clear that stricken bats fall off this energy tightrope. They cannot seem to slow their metabolisms as much as healthy bats. And they arouse much too often, squandering a winter’s worth of calories by around February. The victims starve.
During gentler times for bats, Bucknell University knocked out cinderblock walls to turn part of a basement into a vivarium, complete with climate-controlled hibernation chambers and a room-size flight cage. There, Reeder had planned to study the animals’ stunning coping mechanisms. Instead, much of her vivarium has been devoted to trying to understand – and perhaps combat – whatever is killing bats across the northeastern United States. This fall and winter, Reeder and her students have been collecting healthy and sick bats to study their hibernation patterns. Her group has also been testing anti-fungal chemicals that might be used to treat or prevent white nose syndrome. So far, she has judged one possible preventive treatment safe enough to be released into the air in a test cave. She recommended against another after some healthy bats treated with it died.
To avoid disrupting her captive colony more than necessary, Reeder and her students leave the lights off in the windowless vivarium rooms. They wear headlamps, casting spots of light that bob in the murk. They speak softly, preserving a cavelike hush. Before entering the flight cage to work among the bats, the researchers pull on thick garden gloves. Inside, a bat flaps slowly across the expanse, disturbed by the noise, then settles back onto a wall. The cage floor gives softly underfoot as they enter. It is a wrestling mat, to cushion the fall of any animal that might drop to the floor. It’s covered with long strips of white paper, flecked with bat droppings. One of Reeder’s students carefully eases a bat from one cage wall, conscious of the animal’s knees, which articulate backward compared with human knees. The bats are getting the spray-on treatment that Reeder later will reject as potentially dangerous. They are not happy. The first one, a female, is 14 grams of fury. She twists and chitters, a high-pitched staccato shriek. She bares her teeth. They gleam white inside her pink mouth like little pearl daggers. “Oh, honey, it’s OK,” one of Reeder’s students coos to the bat.
Cupped in the researchers’ hands, illuminated by circles of light, these bats are exquisitely wrought. Their wing membranes stretch between lightweight, elongated bones that correspond to bones in our middle finger, ring finger and pinky. Veins spread through the wings like lace. Reeder rubs the belly of one she is holding and says softly, “Oh, fatty, fatty you are.” At that moment, it is easy to see in her the girl who waited for marmots outside a Sierra cabin, the one who used to go racing home after school to watch Mutual of Omaha’s “Wild Kingdom.” Reeder examines the animal’s soft brown pelt, the shiny black eyes that see superbly, the peaked ears that echolocate even better. “She’s in great shape,” Reeder says. “There’s not so many organisms that you can say, ‘Oh, fat, good for you.’ ”
Reeder delights in this one fat, healthy bat.
So far, white nose syndrome has rampaged through six bat species, striking the little brown bat and the tri-colored bat especially hard. Researchers tracking the syndrome believe it could drive some endangered species into extinction and slash the populations of others. It could also drastically change the patterns of which bat species can thrive in colder climates. Migrating bats are likely to survive, but hibernating species could take decades to rebound, if they ever do, because they breed slowly, often producing just one pup a year.
With at least two endangered species in the syndrome’s path, biologists will not rule out the weird, the long-shot, the improbable response. Late last year, the U.S. Fish and Wildlife Service awarded a grant to round up Virginia big-eared bats and try to breed some in safety. It’s difficult to keep bats in captivity, and no one has ever tried with this species. Reeder and others have been looking for something, anything, that might protect bats without disrupting the delicate ecology of a cave. They had even considered having treatment teams enter a cave and spray the wings of every bat inside.
Meanwhile, researchers are pleading with people to stay out of caves and mines that might be infected. Geomyces destructans can survive at least a week at warm temperatures, long enough to hitch a ride on muddy shoes or caving gear, through an airport and to another cave thousands of miles away. The word has mostly gotten out to biologists and serious cave enthusiasts, who can follow frequently updated online advice about the best precautionary measures. Tougher to reach are the amateur hobbyists, the casual church or scouting groups that might visit an infected cave and never know what they have done.
If white nose syndrome spreads only bat to bat, it’s difficult to say if or when it would cross the Rockies. Before diseased bats could reach the mountain range, the infection might be stopped or slowed in regions with fewer caves and lower bat population densities. One of the leading theories about white nose syndrome, though, is that this fungus has already crossed the Atlantic with human help. To spread the syndrome to the West, Reeder says, “All it will take is one careless caver to take their caving gear into California or into Colorado.”
DeeAnn Reeder and graduate student Roy Jacob examine a bat in 2007. Reeder hopes to find out why a mysterious
ailment has wiped out millions of bats in the Northeast, and whether the plague could spread across the country.
Carrie Peyton Dahlberg
