It’s officially mid-October, and if you haven’t picked up a few Halloween decorations already, you’re probably thinking about it. If you’re the type to go all-out, your home may already be covered in symbols of jack o' lanterns, black cats, witch hats, and… bats. How did these mosquito-snacking mammals become associated with spooky season, anyway? There are a few different theories out there.
Experts say that nocturnal animals are often associated with death and darkness. "They engage in mysterious activities in the dark and so they have been cloaked in superstition since ancient times,” Stanford University classics scholar Adrienne Mayor told National Geographic. And bats are particularly spooky. “The combination of dark gray, brown, or black shades with cryptic nighttime habits evoked a sense of awe and fear back in the time when the only lights at night were oil lamps and wax candles."
Bats’ nocturnal nature, combined with the fact that they often live in caves, gave them a historic “association with the underworld and death,” according to the Library Of Congress. Folklorist Frank C. Brown documented that in the early 20th century, many Americans associated bats with death or bad luck. And the fallen angel Ariel was often depicted as riding on a bat, as far back as Shakespeare’s time.
They’re an in-between kind of animal
Bats are the only flying mammal, and some cultures consider them a “liminal” animal — not quite a bird, not quite a mammal. Something else liminal? Halloween. "One of the main themes of Halloween is liminality — the in-between-ness. It's between one state and another state; between growth and death; between fall and winter, the beginning of the new year. There are all sorts of symbols of that in-between-ness," Steve Siporin, a history professor and folklorist at Utah State University, told Popular Science.
Blame Bram Stoker
According to the Library of Congress, it’s not clear when bats became associated with vampires, but examples appear in the vampire fiction of the late 1700s and 1800s. In the best-known example of this genre, Bram Stoker’s 1897 novel Dracula, vampires can turn into bats at will: “I thought it well to know if possible where the Count would go when he left the house. I did not see him; but I saw a bat rise from Renfield’s window, and flap westward,” the character Quincey Morris recounts.
Others say that bats have been associated with Halloween for hundreds of years, thanks to Samhain, a Celtic harvest festival. Celebrations involve lighting bonfires, which attract bugs — which, in turn, attract bug-munching bats.
In a slightly different theory, Nate Fuller, a graduate student in Boston University’s bat biology program, told Quartz that when Irish and Scottish immigrants came to the United States, they began to associate bats with Samhain, simply because of the timing. Some species of bats will hibernate or fly south for the winter, so in the northern U.S., you can see them swarming in October and November.
We just don’t understand them
Some experts believe that bats are associated with Halloween because they’re just, well, weird. "People fear what we don't understand, and with bats nocturnal, and tending to be small, they're cryptic," Joy O'Keefe, director of the Indiana State University Bat Center, told Popular Science. "Even us bat biologists don't know a heck of a lot about them. It only takes a few wrong turns to perpetuate myths and fears about bats."
But although they might be creepy, bats are also helpful to the environment. They eat bugs — so many that, according to the National Wildlife Foundation, they save us between $3.7 and $54 billion in pest control services every year. They also help pollinate over 700 plants, including many we love to eat, such as avocados, bananas, peaches, and mangoes. So when you put up bat-shaped wall stickers before your Halloween party, remember that they help us humans, even if they freak us out.