Bats By the Bay

By Henry S. Parker

          It’s a familiar scene on a Summer evening in many houses across America. Someone screams, another person swats at the air with a broom and a small winged creature, likely more startled than the humans, swoops and dives among the furniture. At least it used to be a familiar scene. Now, not so much.

Phobias and Facts

Bats are among the least appreciated and most reviled animals on earth. For centuries they have symbolized the evil spirits of darkness: swift, fanged phantoms cloaked in filth, bearing dread diseases and thirsting for our blood. Like all unfounded fears, bat phobia is based on a smidgeon of fact. Some bats can carry diseases. A few—about a half percent in the U.S.—harbor the rabies virus. Fruit bats are known carriers of Ebola in Africa. But these winged mammals pose only a tiny health risk to humans.  Your odds of dying from a bat-transmitted disease are less than one in a million, far smaller than from a dog attack or bee sting.

As for being dirty, bats regularly clean and groom themselves. And their reputation for bloodsucking? It’s true that three species of bats do dine on blood. But they live only in Latin America, prey principally on four-legged mammals like cattle, and, unlike vampires of lore, don’t actually suck gore, they lick it from an incision on the skin.

Getting to Know Them

Bats can be found worldwide, comprising nearly 1,000 species—almost 20 percent of all mammal species— and representing a bewildering variety of forms and behaviors. They range in size from the aptly named Bumblebee Bat to the Flying Fox, a fruit bat whose wing span approaches six feet. Their diets include insects, fruits and even small animals. While they mainly use echolocation for navigating and locating prey, bats can see quite well, especially in the dark. Most are nocturnal, roosting upside down in colonies during daylight hours in trees, caves and other sheltered places.

Limited space and deference to the proprieties of a family magazine prevent detailing the complex, fascinating sex lives of bats. When all is said and done, the gestating mother gives birth after two to nine months, depending on species—usually to a single, helpless pup.

Man’s Best Friend?

Humans would be in big trouble without these creatures. Many bats consume half their weight in insects every night, including mosquitoes and agricultural pests like corn borers, potato beetles and stink bugs, reducing or eliminating the need for chemical pesticides. They pollinate flowers and disperse the seeds of important tropical plants. Imagine a world without margaritas. It could happen if bats disappear because they pollinate agave plants, the source of tequila. Bats are worth billions of dollars annually to the U.S. agricultural industry.

Bats’ Worst Enemy?

We are no friend to bats. When we cut our forests we reduce their habitats. Our wind turbines kill tens of thousands of bats every year in the mid-Atlantic states alone. Our use of pesticides and herbicides threatens their populations. Our burgeoning interest in caving has altered the once-stable ecology of caves where they roost. We eat bats—really. In parts of the South Pacific so many fruit bats have ended up on the dinner table that they are now endangered. And we slay bats deliberately, sometimes reducing it to a blood sport. So, like sharks, bats have far more to fear from us than we from them. Admittedly, that’s small comfort to people who suddenly find bats in their midst.

Where Have All the Bats Gone?

In the last seven years a devastating fungal disease of bats—White-Nose Syndrome —has expanded from a cave in upstate New York to 22 states and five Canadian provinces, killing more than seven million bats to date. Mid-Atlantic states have been particularly hard-hit. Surveyed
populations here of six species, including the common Little Brown Bat, have shown mortality rates approaching 90 percent.

The disease agent is similar to a European fungus.  But where Old World bats have not been susceptible, afflicted American bats develop a creeping white fuzz during Winter hibernation. The fungus, which thrives in the constantly cool temperatures of caves and mines, evidently causes bats to prematurely leave their hibernation sites. With energy reserves depleted, they die in large numbers. Despite growing awareness of the syndrome and a comprehensive research program, the disease continues to spread.

What Can You Do?

You can help. Here’s how:

  • Stay out of caves.
  • Install a bat house on your property. You’ll find ample information resources on line at or
  • Educate yourself about bats and White-Nose Syndrome.
  • Support bat conservation and research efforts.
  • Remember that bats are our friends. You don’t have to hug them, but you should learn to love them.

Henry is an adjunct associate professor at Georgetown University. He previously directed research programs at the U.S. Department of Agriculture and taught marine sciences at the University of Massachusetts Dartmouth. He can be reached at [email protected]

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