Bats Likely Originated In Europe 60 Million Years Ago

Genome Study Traces the Origin of Bats and Flight Back to Europe

Bats probably did not take their first flight over Africa, Asia, or North America, as earlier theories held. They most likely took flight over Europe, roughly 60 million years ago, according to a genomic study of 103 bat species published in the journal Nature.

A team working with the Bat1K project, an effort to sequence the genome of every living bat species, built the most detailed bat family tree yet assembled. Combining genetic data from 103 bat species with 44 ancient fossils, the team overturned earlier theories and reshuffled how several bat groups relate to one another, in ways that surprised the scientists themselves.

This matters beyond a simple map correction. Bats make up more than one fifth of all living mammal species, the second largest mammal group on Earth. They live far longer than their size would predict, carry a range of viruses without obvious signs of illness, and are the only mammals that can truly fly. How bats picked up these unusual traits has puzzled scientists for years, and this research offers an answer.

Genetic Evidence Retraces Bat Evolution to Europe

Piecing together how bats evolved has always been tough, because bats break the normal rules of animal detective work. They fly, so a single species can spread across huge distances fast, making geography an unreliable clue to where a group started. Their fossil record is thin too, mostly scattered teeth and bone fragments, aside from a few exceptionally well-preserved sites from about 56 to 52 million years ago.

To close these gaps, researchers built full genetic maps for 103 bat species, including 42 sequenced for the first time. That collection covered all 21 living bat families, including rare, little-studied groups such as a bat family found only in Thailand and Myanmar, another found only in New Zealand, and the sucker-footed bats of Madagascar. The team also built a database of nearly 700 physical traits across 65 species, including 44 fossil bats.

Scientists ran the genetic and fossil information through several types of analysis and compared the results against each other, a way of checking their own work. When separate methods, including ones based on genes less likely to be shaped by natural selection, kept landing on the same conclusions, researchers felt confident they were seeing something real rather than a fluke of the data.

One of the oddest discoveries involved the sucker-footed bat family found only in Madagascar. Earlier studies had grouped this family with bats from Central and South America. The new analysis instead placed it as the earliest branch of a completely different, unrelated group. Only 22% of individual genes supported that placement when examined alone, showing how much conflicting signal sat buried in the data before researchers viewed the whole genome.

Researchers also untangled a stubborn puzzle involving one tricky bat group, where different sections of the genome told different stories about how it fit in with its neighbors. They traced the confusion to ancient interbreeding between bat lineages after those lineages had already begun to split apart, a process that can blur the genetic signal scientists use to build family trees. Focusing on a genome stretch that resists this kind of mixing brought a clearer history into view.

Fossil Dating Places Bat Origins Around 60 Million Years Ago

On the fossil side, researchers combined fossil ages with genetic data using a method that estimates not just when bats first appeared, but where. Results pointed to a European ancestor living around 60 million years ago, whose descendants split into two major branches: one that arose in Africa and later spread into Asia and Europe, and another that stayed and diversified in Europe. Both branches radiated within a narrow window roughly 56 to 52 million years ago, a period of sharp global warming, with later expansions into the Americas and Australia over several million years.

A fossil called Vielasia turned out to matter a great deal here. Placing it into the oldest known bat grouping gave researchers support for the idea that echolocation, the ability to navigate by sound made in the throat, may have already existed before today’s major bat groups branched off from one another. Flight and echolocation, in other words, may have developed side by side.

Digging deeper into the genomes, the team worked out that the ancestor of all bats likely had 26 distinct chromosomes. As different bat lineages evolved, their chromosomes tended to fuse together rather than break apart, a pattern that showed up across most of the 103 genomes studied.

Bat Evolution Findings Reshape Research on Aging and Disease

Understanding where bats came from is not just trivia for biologists. Bats already sit at the center of research into aging, immune resistance, and disease tolerance, since many species dodge illness and age more slowly than other mammals their size. A more accurate map of how bats relate to each other gives scientists a better foundation for figuring out when and how these traits evolved, rather than assuming they arose independently in unrelated groups.

Scientists behind this work say their approach, pairing large-scale genetic data with a carefully checked fossil record, could serve as a model for other messy evolutionary histories, not only bats. For now, the main takeaway stands on its own: the small, flying mammals seen at dusk across the globe likely trace their roots back to Europe, not the continents earlier theories had pointed to.

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