By BARABARA CLARK
The mystique of bats has played a major role throughout history, in our folklore traditions and in thousands of captivating stories about these denizens of the night.
In “Aesop’s Fables,” a famous collection of moral tales that dates back more than 2,000 years, a particular bat was famously able to escape with his life by convincing his captor, a weasel who was looking to eat him for lunch, that he was not one kind of creature, but another. And then, later, its opposite.
To the weasel who accused him of being an enemy of all birds because of his un-birdlike appearance: “Look at me!” he cries, I’m a mouse, not a bird.” The weasel agrees. Later, he successfully escapes the clutches of another weasel who declares he’d never let a mouse go free: “I am a bird! See my wings.” Both descriptions tally, and the bat goes free.
Notable Night Flyers
Bats are mammals, of the order Chiroptera. With their forelegs amazingly adapted as a wing structure, they’re the only mammals capable of true flight. They’re not rodents, so they don’t chew wood or wire—another bat myth dispelled. They’re rich in number of species—more than 1,300 kinds of bats exist around the world.
Some hibernate, or winter over, in the areas where they nest. Others fly away to warmer climates to feed. The wildlife organization BiodiversityWorks said one bat feeding on Cape Cod and tagged with a radio transmitter (or nanotag) was picked up by a wildlife tracking tower at Naushon on October 19 and clocked in at Skidmore Island, Virginia, on October 24.
Bats fascinate us with their curious appearance and mythic story-hour presence. On the opposite end of the spectrum, too, bats inspire science and technology experts with their echolocation skills and aerial acrobatics. These tiny mammals emit high-frequency ultrasound waves and then listen to the returning echoes to help locate their prey. This technique has helped scientists in the development of marine sonar as well as the use of ultrasound in medical equipment.
For other useful technologies, new types of drones with thin, flexible wings are under development, based on studying the wings of bats. And the National Institutes of Health (NIH) is studying a protein that occurs in bats and helps them survive viral diseases for its possible use in anti-inflammatory treatments in human medicine. More than 80 distinct medicines are derived from plants that rely on bat pollination for their survival.
Bats: An Important Link In Our Ecosystem
Big brown bats, little brown bats—it sounds like the beginning of a children’s rhyme, but it actually refers to two of the main species of bats that inhabit the forests and skies around Cape Cod and its surrounding islands. Along with the northern long-eared bat, these are the three most-numerous types of bats that live, nest and reproduce here, in apparent defiance of white nose syndrome (WNS), the deadly fungal disease that has caused bat populations to plummet in recent years. The US Fish and Wildlife Service has called it “one of the worst wildlife diseases in modern times.” It’s found in the United States and Canada across 12 species of bats.
Bats have suffered severe population declines of as much as 90% in many colonies in the Cape Cod region since WNS became prevalent in this area around 2010. Government agencies such as the Cape Cod National Seashore, along with private local wildlife organizations, have stepped up to try and find ways to mitigate the deadly consequences of the disease.
One of these, BiodiversityWorks in Vineyard Haven, researches and monitors bat populations centered in the Martha’s Vineyard region. The northern long-eared bat is one of the area’s bat populations that is now in danger of extinction. These small bats, similar to little brown bats (also seriously endangered), are about 3 to 3½ inches long, with a wingspan of 9 to 11 inches. They can be distinguished from little browns by a longer tail and thinner, longer ears.
In greatly lowered numbers these bats have persisted in our local coastal areas, and wildlife groups are working to understand their habits and activities and the reasons why they still manage to survive in this region.
Luanne Johnson, a wildlife biologist and the director of BiodiversityWorks, has been working alongside Danielle O’Dell, a wildlife research ecologist at the Nantucket Conservation Foundation (NCF), to help determine some likely reasons why this population is hanging on, in spite of the fact that numbers are plummeting, along with those of the little and big browns.
First and foremost, said Johnson, they hibernate (called “torpor” in shorter hibernation cycles) locally. Because our winters “are milder and shorter, they are surviving [WNS] because they emerge from hibernation early in April and can begin to feed…. With their body temperature warmer and their immune system awake, they can fight off the infection.”
Because the bats are more active for longer periods, fungus levels can remain much lower throughout the season, allowing their immune systems to “learn and build resistance.” Johnson said her organization “has banded northern long-ears that are surviving multiple years” despite having WNS infection. “Each winter a northern long-eared bat survives is another opportunity” to allow this population to survive.
The long-ears on Nantucket have shown similar aspects, said O’Dell. They tend to hibernate in small groups, “often as small as five or 10,” she said, lessening opportunities to spread the disease. It’s milder here, “so they are more active, feeding and hydrating.” The hibernation period may be three to four months instead of the more-common five or six. “Because they’re active longer, they have more chance to develop genetic resistance to WNS.”
Johnson added, “Our little brown bat colonies are [also] recovering and showing resistance [to WNS]. Their immune systems seem to have given them an advantage over their cousins.”
Goodbye, Bananas
Why should I mind if bats disappear? First of all, we could kiss bananas, avocados and mangoes goodbye from our diets. Bats are essential pollinators for many fruit and plant crops, including those delicious staples. Other food losses would include peaches, cloves and the important sweetener agave.
Besides all that, bats fill crucial roles in seed dispersal and as pollinators. It’s all an integral part of an ongoing, healthy ecosystem. More than 99% of existing US bat species are insectivores, hard at work for more than six months of every year, eating millions of moths, crop pests, invasives, mosquitoes, beetles and other insects that damage local crops and trees. Recent studies estimate that bats eat enough pests to save more than $3 billion per year in commercial pest control costs.
Bats offer “organic, effective and free pest control,” conservationist Jennifer Longsdorf said in an article for Massachusetts Wildlife. They’re important at every juncture. At ground level, bat guano is a rich fertilizer. And apart from their insect-control skills, bats themselves are a food source for other species. It’s all connected.
Humans Can Help Protect And Encourage Survival In Bat Colonies
Disease, habitat loss and pesticide use—all have contributed to severe numbers loss in the bat population. Both Johnson and O’Dell are in agreement on a number of ways humans can work to encourage the survival of local bat colonies.
Help protect bats’ natural habitat. Allow dead or dying trees that don’t pose a hazard to remain—they provide a major roosting spot for bats.
If you need to evict bats from an attic space, where they like to overwinter, do so carefully and humanely so that they survive and can move elsewhere. Roosting spots can be emptied only in early spring or late summer into fall—summertime is nesting time, so it’s illegal to evict an endangered species then.
Likewise, older homes with dirt crawl spaces underneath can often house bats looking for a safe place to spend the cold months. Your basement crawl space could be such a habitat. If such a house is being demolished, check whether bats are roosting and evict carefully, so they survive the move to live and nest elsewhere. Of bats in a crawl space, remember, said Johnson, “they are excellent tenants compared to mice.”
Consider installing a proper bat house on your property, on a high pole or on the side of a building that gets lots of sun. Once bats have decided to move in, they will keep returning year after year, consuming thousands of harmful insects. Bats can also find shelter behind boards, shingles or shutters.
And more: Reduce pesticide use—bats feast on many plants that may have been sprayed with poisons…. Night-blooming flowers can attract bats that will spend time in your garden…. Keep your cat indoors.
Finally, do your homework. Help dispel the bat myths that may keep wary humans from helping these small creatures to survive.
Their populations are now very fragile, O’Dell said. But regardless of the “value” of bats to us and the ecosystem around us, we should not have to “prove” how useful these creatures are in order to want to save them. “They’re here; they evolved. They can fit into the ecosystem in ways we may not always understand. But that’s OK. All are important.”
More Information
Bat Conservation and Management (https://batmanagement.com): Fact sheets and information about building and installing bat houses.
Bat Myths and Folktales From Around the World (https://folklorethursday.com/), 2019.
National Park Service (https://www.nps.gov/subjects/bats/benefits-of-bats.htm#) article: “The Benefits of Bats.”
US Fish and Wildlife Service (https://www.whitenosesyndrome.org/): Info on white nose syndrome.
Print article: “Bat Myths Debunked” by Jennifer Longsdorf, Massachusetts Wildlife, January 7, 2020. PDF available on Adobe Acrobat.