Major genome study reveals bats emerged in Europe 65M years ago, rewrites evolutionary tree

Bats have always been difficult to know. They roost in darkness, in places humans cannot easily reach. They live longer than other mammals their size. They navigate by sound in ways that seem to defy physics. They fly with a grace that no other mammal can match. Yet for all their visibility in the night sky, their evolutionary past has remained largely hidden—their fossil record sparse, their genetic relationships unclear, their origins a puzzle that has frustrated scientists for decades.

A study published in Nature this year changes that. Researchers working on the Bat1K project, an ambitious effort to sequence the genomes of every living bat species, have completed the first phase of their work. They analyzed genetic material from 103 bat species representing all 21 living bat families, then compared those genomes with fossil evidence to construct a new evolutionary tree. The result is a fundamental reordering of how scientists understand bat relationships—and a clearer picture of where and when bats first appeared on Earth.

The findings point to Europe as the birthplace of bats, roughly 65 million years ago. From there, the evidence suggests, they dispersed into Africa and across the globe, eventually becoming one of the most successful mammalian lineages. Today, bats comprise more than one-fifth of all mammal species, with roughly 1,500 living species inhabiting every continent except Antarctica. Yet until now, scientists have disagreed fundamentally about how different bat families relate to one another. The new tree, built from comparing full genomes and specific chromosomes across the entire order, contradicts several long-held assumptions. Sucker-footed bats from Madagascar, for instance, were previously thought to be closely related to neotropical families. The new analysis places them instead within the superfamily containing vesper bats—the most abundant bats on Earth. That same group is now shown to be closely related to sac-winged bats, which were previously considered distant relatives.

Ariadna Morales, an evolutionary biologist at the American Museum of Natural History and a co-author of the paper, described the shift plainly: the evolutionary tree of bats has changed. Different regions of the genome, she noted, tell different stories. By synthesizing those stories—by comparing genetic sequences across multiple parts of the genome and layering that analysis against the fossil record—the researchers were able to map divergence points with new precision. The convergence of multiple lines of evidence made the case for Europe as the ancestral homeland unusually strong, even as Africa and Asia remained plausible alternatives.

The study also reopens a question that has divided bat researchers for years: whether flight or echolocation evolved first. A 2008 study had favored flight as the primary innovation. This larger dataset suggests that echolocation appeared before modern bat lineages diversified—meaning both abilities may have emerged at the base of the evolutionary tree, before bats split into the families we see today. Nancy Simmons, curator emerita at the American Museum of Natural History, acknowledged the shift: the evidence now points to flight and echolocation evolving together at the foundation of the bat order, though which came first remains unknown.

Emma Teeling, a zoologist at University College Dublin and co-director of the Bat1K project, framed the work as a beginning rather than an ending. Bats are the most extraordinary of all mammalian lineages, she said. This study is a springboard. The new evolutionary tree provides a foundation for the next phase of research—identifying the specific genes responsible for powered flight, for the biological sonar that allows bats to hunt in complete darkness, for the unusual disease resistance that lets bats carry viruses without falling ill. The genetic blueprint is now in hand. The work of understanding how bats became what they are has only just begun.