Just in Time for Halloween, Scientists Are Preparing for a Vampire Bat Invasion in the U.S.

Researchers believe climate change contributes to the cause

Photo: Getty Images

Tis the season … for stockpiling copious amounts of garlic, crosses and holy water to fight vampires. Vampire bats, to be specific.

OK, maybe that’s just in the movies, but according to Popular Science, vampire bats may soon swarm the United States in droves unseen since 5,000-plus years ago. The likely cause? Climate change.

Fossils found in California, Florida, Texas and Arizona (among other states), dating back to approximately 5,000 to 30,000 years ago, indicate that the vampire bat once lived in the U.S. when it was a much warmer place. The species is currently found throughout Mexico, Central America and South America, but research shows that the Desmodus rotundus population is on the rise, pushing into new territory in both North and South America. The bats may bring new variants of rabies along with them.

“We’re not trying to portray these animals as something we should all be scared of,” says Antoinette Piaggio, a molecular ecologist at the U.S. Department of Agriculture who co-authored the study, published in July. Vampire bats are “very social and gregarious animals,” according to Piaggio, “that have coexisted with humans for a really long time.”

However, these flying mammals (the only ones to feed solely on blood), are not well-suited to cold weather. They tend to live in areas where the temperature does not dip below 50 degrees Fahrenheit. And yet, within the past five years, the bats have been documented as close as 30 miles away from Texas. The researchers do admit that bat speed is relative; they could’ve started migrating northward in the last decade or over the past few hundred years.

That said, if the climate in southern states continue to shift, with winters becoming warmer, the bats have a decent chance of survival here.

“I think it’s going to be a pretty slow invasion,” Daniel Streicker, a disease ecologist at the University of Glasgow in Scotland, tells Popular Science. However, he says he doesn’t “see why they couldn’t move up into the U.S.”

Currently, rabies is not found in the vampire bats along the west coast of South America. But researchers studying how the species meets and mingles are trying to understand how and where the vampire bat meetups occur, which could be key in tracking rabies virus outbreaks.

Rabies outbreaks among cattle in Peru have led farmers to report the vampire bats to Streicker. The bats have always been there; the virus affecting their livestock is a new problem. Rabies appears to be on the move in the region; possibly due to the way climate change affects the mountainous area. A warmer climate may allow once-impassable mountain ranges to be traversed by the bats, which in turn assists their ability to mate and spread disease among new colonies.

Before the general public goes batty (pun intended) about this potential health issue, know that the U.S. Department of Agriculture’s National Rabies Management Program has examined more than 95,000 cattle for vampire bat wounds in Texas, Arizona and Florida in 2017. It has not found evidence of bites or new strains of rabies yet, and the department is educating farmers and wildlife biologists on the border states so they can remain vigilant.

“While the mention of the word rabies strikes fear [into] people there are very straightforward ways to minimize the risk of being exposed,” Richard Chipman, the department’s rabies management coordinator, told Popular Science. “Vaccinating pets and livestock and avoiding strange or sick acting wildlife remains the best first line of defense.”

While their possible swarming descent upon America’s southern states sounds like something out of a horror movie, Chipman assures that “The arrival of this unique and interesting species and eventually a novel (at least in the U.S.) rabies virus variant is not a catastrophic event or cause for significant alarm.”