The flying mammals likely arose 65 million years ago in Europe, before spreading to Africa and then the rest of the world, according to the new research

The common vampire bat (Desmodus rotundus) is one of 1,500 species of bats around the world. Brock and Sherri Fenton / Wildlife Conservation Society

Bats are among the most extraordinary creatures on Earth. With 1,500 species spread across every continent except Antarctica, they make up about one-fifth of all mammal species and rank as the second most diverse group of mammals, after rodents. They’re the only mammals that can truly fly, they use echolocation to “see” in the dark, and they’re highly resistant to disease, carrying a variety of fatal viruses while seemingly never getting sick themselves.

Yet the origins of bats have remained mysterious—until now. The airborne mammals likely arose 65 million years ago in Europe, rather than in Africa, North America or Asia, as had previously been suggested, according to a study published September 23 in the journal Nature. The work provides a new evolutionary family tree for bats, shedding light on the various species’ evolutionary histories and relationships with one another.

What’s more, the study represents largest-ever analysis of bat genomes, or complete sets of genetic instructions, and fossils. And scientists say it’s just the beginning. The paper lays the groundwork for future research into how bats evolved unique adaptations like echolocation, flight and disease resistance.

“It finally gives us a robust, resolved family tree and biogeography, something that’s eluded scientists for decades,” study co-author Sonja Vernes, a biologist at the University of St. Andrews in Scotland, tells Live Science’s Sascha Pare. “Get the tree right, and everything else about bat evolution starts to fall into place.”

Vernes and colleagues analyzed the genomes of 103 species from all 21 living bat families. They also compared physical characteristics across 65 species, including 44 bat fossils and members of most extant bat families. The team—made up of more than 130 scientists from around the world—used the combined data to chart relationships between different bat groups, estimate when their evolutionary lineages diverged and investigate where bats originated and how they spread around the globe.

After the animals arose in Europe, the evidence suggests they ventured into Africa, before expanding to Asia, the Americas and Australia. “Because bats are flying … they’ve been dispersing all over the world and crisscrossing the planet for millions of years,” Vernes tells CBC News’ Emily Chung.

The results also add to the debate over whether echolocation or flight evolved first in bats. A prominent study published in 2008 suggested that flight came first. But the new research, which is based on a bigger dataset, muddies that conclusion by pushing back the timeline on echolocation.

“Now we’re sort of back where we were a number of years ago, which is flight and echolocation seem to have evolved at the base of the tree,” Nancy Simmons, a curator emerita at the American Museum of Natural History who co-authored both the 2008 paper and the new study, tells the New York Times’ Emily Anthes. “And we still don’t know whether they came at the same time, or one came before the other.”

The new study is part of Bat1K, a global initiative launched in 2017 that aims to sequence and analyze the genomes of every living bat species. Moving forward, the project’s findings could help support conservation efforts, as bats face threats like habitat loss, climate change, collisions with windmill turbines and disease.

One of the most pressing examples is white-nose syndrome, a fatal fungal disease that infects bats that hibernate each winter. Discovered in 2006, the disease has since spread across the United States and Canada and killed millions of bats.

“There may be some interesting findings that other researchers can take from this study … to go back and piece together what’s happening with white nose syndrome,” study co-author Sarah Olson, director of health research at the nonprofit Wildlife Conservation Society, tells the Guardian’s Gloria Dickie.

Additionally, the team’s work could help scientists uncover the genetic underpinnings of some of bats’ distinctive traits, such as their exceptionally long lifespans for their size—around ten times longer than expected—and their resistance to viruses that cause diseases like Ebola, Nipah and Marburg in people.

That research may ultimately lead to insights that could benefit human health, including treatments for zoonotic diseases or even cancer.

“The world should be paying particular attention to bats, both because they are so special and unique in the wildlife kingdom—and that alone should be enough for us to be able to conserve them,” Joe Walston, executive vice president for global conservation for the Wildlife Conservation Society who was not involved with the study, tells the Washington Post’s Sydney Goitia-Doran. “But in addition to that, they hold so many possibilities for the betterment of humankind.”

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