Something in the night
Scientists paid little attention to bats until a decade ago, when a disease called white nose syndrome started wiping out populations across the United States. Now, researchers race against time to find out what bats — and their disappearance — mean for the world at large.
By Jack Evans
MORGAN-MONROE STATE FOREST — The light turns gold as the pickup bumps along Goose Creek Road. By the time the researchers reach their destination, the sun has maybe an hour left in the sky. This is part of the plan. Tonight’s quarry lives in the dark.
When night falls, they work in the glow of headlamps. They rig nets in the soft earth around a pond, and they lie in wait until the netting snags their prey. In latex-gloved hands, they cradle piggish faces squeaking above bodies no bigger than human palms. They inspect the translucent wings for signs of the disease wiping out these creatures.
Then they open their hands and watch the bats fly back into the night.
“That’s so cool,” researcher Hannah Friend says.
Sometimes the bats seem like nothing more than ghosts, half-seen figments fluttering across a swatch of sky. They elude the researchers on some nights, and fewer appear each year — as if the caves where they winter have claimed them entirely.
A fungus-borne menace called white nose syndrome has massacred bat populations across the country over the past decade, rendering the species in some places functionally extinct. White nose has gnawed at Indiana, but not as thoroughly as it has some other regions, which makes the state ripe for research.
Even as species such as the Indiana bat and the northern long-ear disappear, scientists know relatively little about them. Widespread interest only blossomed a decade ago, when biologists found themselves pressed for time by a fungus with a comically evil scientific name, Pseudogymnoascus destructans.
Long deemed pests, predators and plague-bringers, bats may play crucial roles in their environments, in agriculture and in human health. So now, deep in these woods, the researchers work into the night taking samples of fur and droppings. They hope to find, while there’s still time, what the world stands to lose.
For centuries, humans have consigned bats to realms of danger, disease and death. Leviticus tells believers to “regard (them) as unclean.” The Mayan bat god Camazotz killed humans with sharp-pointed weapons. In parts of southwest Asia, bats have long been regarded as omens of bad luck or death.
Researchers and journalists in the last century have documented those fears turning into violence. In his book “The Secret Lives of Bats,” preeminent bat researcher and conservationist Merlin Tuttle remembered seeing people in Venezuela use flamethrowers to kill vampire bats.
Human disturbance, including cave vandalism, led to the listing in the late 1960s of the Indiana bat as endangered, a designation it retained even before white nose syndrome appeared. Now, the species hibernates in just a handful of caves across the Midwest.
Even biology and environmental science largely ignored bats until recently, said Timothy Divoll, who has researched bats in southern Indiana’s forests over the past few summers.
The Indiana State University doctoral student’s research on bat diets illustrates the extent of the ambivalence. Though bats in North America have been known to generally eat bugs, Divoll is still cataloging which bugs and understanding what that might mean for their ecosystems.
“People weren’t really intensely studying these species before the decline,” Divoll said. Then white nose came.
Researchers found it first in February 2006 in upstate New York. By 2011, it showed up in Indiana. According to the United States Fish and Wildlife Services, confirmed or suspected cases have surfaced in 33 states and five Canadian provinces.
White nose attacks bats at their most vulnerable. When bats hibernate, they reserve energy so they can survive without eating until spring. Bats with white nose use far more energy during hibernation — as much as twice the amount that healthy bats use, according to a 2015 study.
The vampiric disease doesn’t just kill bats. It sucks the life out of them.
By 2015, the most recent year with data available from the Indiana Department of Natural Resources, the population of Indiana bats had declined by 27 percent over four years in their namesake state. In the same year, the northern long-eared bat, whose range stretches from the east coast to Louisiana, the Dakotas and Canada, became the first species to be listed as threatened under the Endangered Species Act due to white nose.
Some parts of the country have seen 90 to 100 percent mortality rates.
Lizz Beilke, a doctoral student and one of Divoll’s colleagues at ISU, spent last year’s research season in the Great Smoky Mountains along the Tennessee-North Carolina border. White nose reached there in 2009. By last year, she said, both Indiana bats and northern long-eared bats were functionally extinct there. They may have still existed in small numbers, but they could no longer fulfill their roles in their ecosystems.
They were as good as gone.
It is a cool May night, the first of the research season, when the team drives down Goose Creek Road armed with latex and Lysol and long black nets. Divoll parks the truck at the head of a clearing off the road.
They make camp in the clearing and take a footpath to a small, still pond with a glassy black surface. Insects flit through the air above it, their bodies made tiny stars by the golden hour light.
The researchers — Divoll, Beilke, Friend and Lauren Hendrickson — unfurl their mist nets, meter after meter of fine polyester. Even in daylight, against the black surface of the pond, the netting becomes hard to see. When night falls, it disappears entirely.
The researchers hem in one end of the pond. The clang of Divoll’s hammer on metal stakes butts against the woods’ soft birdcalls. When the sun goes down, Divoll explains, the bats will swoop low over the pond to drink and feed on the insects, then — hopefully — fly into the netting and entangle themselves.
“We probably only have a couple of minutes,” Divoll warns Beilke as they finish setting up. The setup has taken more than an hour, and now, with the light receding, they return to the clearing where they made camp to cover their bodies in surgical scrubs or navy-blue coveralls and gloves.
“I feel like I should be in a factory,” Hendrickson jokes, but the precautions are less for their own safety and more for that of the bats. By covering their bodies, bagging personal items and disinfecting surfaces, they hope to keep from spreading any outside diseases or fungi to the bats.
Beilke sets up the bat line — “a clothesline for bats,” as Divoll describes it, where bats, after being removed from the nets, will hang in mesh bags until the researchers examine them. The headlamps glow under an inky sky.
The forest quiets. Beilke and Divoll pick out sounds in the distance — flying squirrels, a whip-poor-will — when they spot a flutter that drops their voices to an excited whisper.
“It’s a tiny one,” Divoll says.
“Hopefully he’ll end up in the nets,” Beilke says.
Then headlamp beams cut along the footpath to the pond and onto the nets, where they illuminate three immobilized bundles.
Divoll makes quick work on the first one, a northern long-eared bat. He untangles it but holds on, his grip gentle but firm. The bat squirms and squawks. A metal band around one wingtip shows it was caught and released by researchers before.
“We got a second one,” Friend calls to Divoll. It’s small and gray, and its hairless toes distinguish it as an exciting find for the researchers.
“Shit — that looks like an Indiana bat,” he says. He untangles it, and it too puts up a fight. “She’s a female. She’s probably pregnant — that’s why she’s getting angry.”
Beilke pulls down one more netted bat, a more common red that fidgets less than the others. Divoll would expect a big catch like this to come at the beginning of the night, he says, with the bats all rushing out at once to feed. But at this point, that anything has happened at all elates them.
“First night!” he says.
“First net check!” Beilke calls back.
By the end of the summer, they’ll catch 19 Indiana bats and eight northern long-eared bats. Divoll will determine anecdotally that areas harvested last year by the DNR don’t prove any less hospitable to bats, and the abundance of dead trees may make for better roosts.
The other aspect of the research, analysis of bats’ droppings to better understand their diets, takes longer. But Divoll has already worked on that research for three years, and in that time, he’s found at least 500 species of insects.
“They’re completely insectivorous,” he explained. “We have many options. Fruits, vegetables, meat, dairy. We can get our nutrition many ways. They can only get it from insects.”
In addition to white nose syndrome, climate change and wildlife management practices that alter bugs’ habitats may put bats at greater risk.
They eat beetles that bore into the bark of trees and wipe out whole sections of forest. They eat moths that damage trees by rolling their leaves. They eat the mosquitos that carry dog heartworm and West Nile virus, and if climate change brings the mosquito that carries the Zika virus this far north, they’ll eat that, too. They eat crop pests that, if left unchecked, could threaten agriculture.
And so, Divoll and other scientists have begun to understand, bats exist at a crucial link in America’s environmental and economic chains. Their tiny wings may be hard to spot in the night sky, but they reach far into worlds beyond their own.
A puff of smoke escapes toward the treetops as Divoll solders two parts of a small metal transmitter, which will help the researchers track the bats and map their roosts.
A few steps away, hunched over a storage tub serving as a work table, Beilke weighs and measures the red bat and takes samples of its fur. When she’s done, Hendrickson and Friend help her attach a metal band. Then they let it go.
They clean their tools and work surfaces with Lysol wipes. An alarm, set for a net check every 10 minutes, sounds — deeeeet deeeeet deeeeet — and a minute later, Divoll returns from the pond with another Indiana bat.
Beilke takes the first Indiana bat from the bat line and spreads her on the work table. Her fingers look huge as they prod the bat’s belly, searching for signs of pregnancy.
“Sometimes you can feel something hard on one side,” Divoll suggests. “The fetus is sideways.” She probes the sides of the bat’s stomach with her fingers.
“Yeah,” she says, and Friend marks a spreadsheet with “P” for “pregnant.”
Now Beilke pulls the bat’s wings taut to look for scarring, a telltale symptom of white nose syndrome. She is undamaged.
The whole crew leans over the table. Beilke spreads out the bat, her back to the sky. Divoll uses scissors to cut a small bald patch in her fur and cleans it with alcohol. Then he dips a brush in surgical cement, daubs it on one side of the transmitter and attaches it to the bald spot. The transmitter will likely fall off after two weeks, he says, or when the bat molts.
When the cement sets, Divoll coaxes her to the end of his fingertips, where she perches. After deciding she’s not going to fly from his hand, he finds a tree to set her on, and she climbs up and into the night.
By 11 p.m., the crew has determined they’re unlikely to catch any more bats tonight.
They sit in a circle of camping chairs in the quiet of the woods, faces bathed in the light of a single headlamp.
They talk about their hopes and anxieties. Uncertainty haunts the immediate future of wildlife research: President Trump has rolled back the U.S.’s federal environmental standards and proposed slashing the Environmental Protection Agency’s budget.
“Right now, in this political climate, it’s so hard to get your heart set on something,” Divoll says.
Every so often, they simply fall silent. Then, all at once, they tilt their heads and look toward the sky.