Bats should be better loved in Mount Vernon


Bats have a bad reputation, from their association with witchcraft to blood-sucking vampires to spreading rabies. But “We couldn’t survive without bats,” Deborah Hammer, a bat educator, told Friends of Dyke Marsh (FODM) on October 26. Hammer is a board member of FODM and Bat Conservation and Rescue of Virginia.

More than 500 species of plants depend on bats to pollinate their flowers, including species of mango, banana, durian, guava and agave. Some plants are partially pollinated by bats, including coffee, chocolate, and sugar.

“If you like to eat, consider bats,” she said. In addition, bats disperse seeds.

Bats are the only mammal capable of true flight, Hammer said, adding, “Their acrobatics are quite extraordinary.” They have elongated forelimbs and wing membranes connected to their long fingers, so basically they “fly with their hands and have the same dexterity as humans,” she said.

Deborah Hammer

Like all mammals, bats have hair, their young are born alive, and mothers feed the young with their milk, she explained. They have keen hearing and are more active at night. Bats have an adaptation called “ecolocation” for finding insects and dodging obstacles in the dark. They are not rodents. Their closest relatives are dogs.

Many species emit a high-pitched chirp that is inaudible to humans. After daylight, most bats roost throughout the day, hanging from tree hollows, caves, or other houses by their hind legs, usually upside down, with their wings draped around their body.

In temperate regions like Virginia, in winter, bats either hibernate or migrate south. In summer, they often roost in trees.

Hammer revealed even more facts about bats: Worldwide, there are about 1,400 species of bats on every continent except the polar regions and some deserts. The smallest bat is the bumblebee bat, weighing around two grams. The largest is the giant golden-crowned flying fox with a wingspan of six feet. Virginia has at least 17 bat species, and observers have seen at least seven bat species in Dyke Marsh. A 2013 survey identified three bat species at Fort Belvoir: the tricolor bat, the big brown bat, and the red bat. “Little brown bats have been recorded at Fort Belvoir before,” the study says, attributing their absence to a harmful fungus, white-nose syndrome.

“Almost all bats in northern Virginia are insect eaters,” Hammer said. A big brown bat can consume 3,000 mosquitoes a night, she noted. “A little brown bat has been documented eating more than 600 mosquitoes in an hour,” reports the Virginia Department of Wildlife Resources.


Global bat populations are declining. A major cause is the loss of foraging or roosting habitat, usually wooded areas near water sources.

Since its discovery in 2006, white nose syndrome has affected bats in at least 35 states and Canada and killed millions. A white fungus appears on the nose, ears and wings of infected bats. Some infected bats exhibit atypical behavior, such as flying outside during the day.

Other threats include outdoor cats, nighttime lighting, pesticides, herbicides, noise, and collisions with power lines, vehicles, and wind turbines.


Have you ever heard the expressions “dingbat”, “going crazy” or “blind as a bat”? People have invented several derogatory and misleading colloquialisms for bats. “Bats see perfectly well,” the DWR website says. Bats are no more likely to have rabies than other rabies vector species, the DWR also notes.

So when it comes to vampire bats, of the 1,400 species, only three drink blood, Hammer explained. They are found in Central and South America.

The program was sponsored by FODM, Friends of Huntley Meadows Park and Friends of Accotink Creek.

How to help bats

“Left alone, bats are harmless and very beneficial,” says Bat Conservation International. Like most wild animals, they want to avoid human contact.

Leave trees dead if they are safe, as many bats roost in tree cavities and spaces between bark and wood.

Set up a bat house, see

Reduce outdoor lighting.

Avoid insecticides.

Stay away from caves and places where bats hibernate.

Keep cats indoors.

More information

Virginia Bat Guide,

conservation of bats, and


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