Bats Hitch a Ride on Storm Fronts When Migrating, Saving Energy by ‘Surfing’ Through the Sky, Study Finds

More than 1,400 species of bats exist worldwide, making them some of the most widespread creatures on Earth—they can be found on every continent except for Antarctica. Chances are, there’s one not too far from you right now. But despite the animals’ prevalence, their migration patterns remain largely a mystery. Their speed, small size and nocturnal nature make studying bats challenging. Now, researchers at the Max Planck Institute of Animal Behavior are shining a rare light inside the “black box” of bat migration.

In a new study published in Science this month, a team of biologists used tiny tags attached between bats’ shoulder blades to track their movements. The tags, which the researchers developed, used the Internet of Things—a wireless network of computers, smartphones and devices that can transfer information—to triangulate the bats’ position.

“On certain nights, we saw an explosion of departures that looked like bat fireworks,” lead author Edward Hurme, a biologist at the Max Planck Institute for Animal Behavior, says in a statement. “We needed to figure out what all these bats were responding to on those particular nights.”

The team followed the movements of 71 female noctule bats (Nyctalus noctula) across central Europe during their spring migrations. They tagged bats across three years, though each bat’s tracker fell off naturally after about four weeks. Originally tagged in Switzerland, the bats later dispersed, flying in a general northeastern direction to Germany, Poland and the Czech Republic, reports Science’s Elizabeth Pennisi. The research revealed that when the bats migrated, they would fly up to 238 miles each night—nearly 125 miles longer than previously thought.

After incorporating weather data into their analysis, the researchers concluded that the bats coordinate their movements with warm fronts that precede storms. These nifty night surfers use the strong winds generated by the front to get a boost to their destination—and expend less energy in the process, according to the paper.

“This was actually a big surprise. We had some clue that bats were responding to good wind conditions, but we didn’t think that there was this connection to storms,” Hurme told NPR’s Jonathan Lambert.

The scientists still don’t know how the bats can predict a storm is coming, but they hope the technology they developed will allow for more bat studies.

“This technology revolutionizes the tracking of bat movements and will surely help researchers answer many questions about migration,” says Charlotte Roemer, a conservation biologist at France’s National Museum of Natural History who was not involved in the study, to Science. “The possibilities are very exciting.”

For instance, further research on this topic might help protect bats from human-caused fatalities, especially as the animals are increasingly endangered. Understanding where and when bats migrate could help wind turbine operators mitigate collisions with the blades, which are the cause of millions of bat deaths globally each year.

“More studies like this will pave the way for a system to forecast bat migration,” Hurme says in the statement. “We can be stewards of bats, helping wind farms to turn off their turbines on nights when bats are streaming through.”

Sara Hashemi | READ MORE

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.