Bats, a diverse group of flying mammals crucial to many ecosystems, first emerged in Europe approximately 65 million years ago, shortly after the mass extinction event that ended the reign of the dinosaurs, according to a comprehensive new study. This research, which combines the largest collection of bat genomes ever assembled with extensive fossil analysis, sheds fresh light on the evolutionary origins and adaptations of these nocturnal animals.

Scientists compiled genome data from 103 bat species, representing all 21 recognized bat families, and integrated these with information from 44 fossil specimens. This combined approach enabled the creation of a detailed bat family tree, clarifying long-standing questions about when and where bats first evolved. The findings indicate that bats originated in Europe, challenging earlier hypotheses that proposed North America, Asia, or Africa as their point of origin.

Following their initial appearance in Europe about a million years after the asteroid impact 66 million years ago, bats are believed to have spread to Africa, making these two continents central to early bat evolution. Researchers note that bats have since diversified to inhabit every continent except Antarctica, now accounting for over one-fifth of all mammal species worldwide.

The study also addresses the evolution of two key bat traits: flight and echolocation. Echolocation, a biological sonar system used by many bats to navigate and hunt in darkness, appears to have evolved near the beginning of bat evolution, closely following the development of flight. “Being able to both fly and echolocate opened up remarkable ecological opportunities,” said Sonja Vernes, a biology professor at the University of St Andrews in Scotland and one of the study’s lead authors. According to Vernes, this combination allowed bats to exploit nighttime niches with reduced competition and predation.

Emma Teeling, a zoology professor at University College Dublin and co-leader of the study, emphasized that echolocation facilitated bats’ nocturnal lifestyle, reducing competition with day-active birds and helping them avoid predators. This adaptation likely played a significant role in their evolutionary success.

The oldest bat fossils identified date back approximately 52 million years, supporting genetic data that place the origin of bats soon after the Cretaceous-Paleogene extinction event. Liliana Davalos, an evolutionary biologist at the State University of New York at Stony Brook and another study leader, pointed out that the post-extinction environment enabled mammals, including bats, to flourish and diversify.

This research not only enhances understanding of bat evolutionary history but also highlights the importance of combining genetic and fossil evidence to unravel the origins of complex traits and species diversification in mammals.