Med thumb swarm of bats

There is the wolf and his transformation. There is the black cat and her hexes. And let’s not forget about the crows — those coal-black harbingers who gather in “murders.” But no animal is such an insignia of autumnal terror as the bat.

The connection makes sense. Bats are ugly things with black pinhole eyes, tiny pig-like snouts, large ears and bony little elbows. Plus, they hang upside down, fly in million-strong swarms and are thought to be the transitional form of vampires. Oh, and they’re known transmitters of rabies and also such other viruses as Nipah and Hendra. Some also believe they’re responsible for transporting Ebola.

But, in reality, they’re not so bad. The ugly little critters actually fight the spread of certain diseases by consuming thousands of Earth’s most notorious killer, the mosquito, every hour. Much like birds, they help spread seeds around (albeit unknowingly). And about that whole Dracula thing, the vampire bat is native to South America and took its name from the myth — not the other way around.  Still, preconceived notions remain strong.

Let us consider just one species, the little brown bat (Myotis lucifugus), among the most common yet also misunderstood creatures in North America. Few know that it is the only mammal that can truly fly — in the sense that it propels itself with the motion of its wings. Other mammals, such as the “flying squirrel,” must settle for gliding with no in-air propulsion. The little brown bat in adored by some as a cute woodland creature, and it is reviled by others as a pest or even demonic presence.

Its unique sleeping habits don’t help make the case for cuteness.


First of all, little brown bats never sleep alone. They roost in groups of up to one million, creating smaller colonies for daily sleeping and larger colonies — known by the Halloween-worthy term hibernacula — during the winter months. It’s these latter cuddle parties that inform the opinion that they’re seasonal pests.

During summer roosting, brown bats can remain asleep throughout daylight hours, which further north can total nearly 20 hours a day. They fly around and forage at night. Autumn is their mating time, and the little brown bat will do its damnedest to breed (and thereby create more body heat for the winter in their hibernacula). The bats’ best chance at making it through harsh northern seasons depends on finding an enclosed place that will trap the moist heat of 100,000 living organisms and snuggling together — much to the chagrin of anyone who happens on their roosts.

For most of the year, the little creatures of the night roost in caves, where the darkness allows them to sleep throughout sunlit hours. Their winter-long shelter, however, is often man-made. Any building big enough to house a hibernacula could be a target. A six-figure strong colony of bats roosts in a barn or similar structure for the winter, they hang upside-down from anything their strong claws can grip, wrapping themselves with their wings in a shape that inspired Dracula and his coffin repose.

This position is not for fear but function. It helps the little warm-blooded creatures retain heat and also take flight. Their relatively tiny legs aren’t strong enough to lift them off the ground and start them flying; hanging upside down far above the ground allows them to simply drop into the air. Because they’re quite social, enormous groups leave the roost at dusk to feast on bugs, fruit and seeds before coming back for another 20-hour lie-down.

While little brown bats aren't dangerous to humans, the sheer numbers of their roosts make them a hard pest to deal with, especially since they spend the majority of their time sleeping in homes or barns. But they don’t mean to be pests. They’re just trying to stay warm. And it’s not their fault they’re ugly.