Bats most likely first evolved in Europe roughly 65 to 60 million years ago, according to a study published Sept. 23 in the journal Nature that combined the largest set of bat genome assemblies gathered to date with evidence from dozens of fossil species. The finding challenges earlier proposals that the world's only flying mammals arose in Asia, Africa or North America.

The study, produced by the international Bat1K genome consortium, also concludes that echolocation, the biological sonar most bats use to navigate and hunt in the dark, appeared near the start of bat evolution, close in time to powered flight.

The work matters beyond the bat family tree. More than 1,500 bat species make up over one-fifth of the world's mammals, and they pollinate plants, disperse seeds and eat vast numbers of insect pests, according to Stony Brook University's announcement, which co-led the research. A clearer evolutionary framework gives scientists a firmer basis for studying the traits behind those ecological roles.

Rethinking a Long-Debated Birthplace

Where bats began has been argued for decades, with Africa, Asia, and North America all proposed. North America had a strong claim in the fossil record. In 2023, researchers described the oldest bat skeletons yet found, from Wyoming rocks about 52 million years old.

Old fossils in one place do not settle where a group first arose, however. Fossils form only under rare conditions, and the oldest specimens found so far may reflect where rocks happened to preserve them. The new study tried to get around that problem by modeling fossil and living species together while accounting for how continents shifted over time.

Liliana M. Dávalos, a professor in the Department of Ecology and Evolution at Stony Brook University in New York and a co-corresponding author, said modeling fossil and living bats together "can do what other methods cannot." The approach, she said, identifies the oldest group of fossil bats while taking the genomic data into account.

The analysis pointed to Europe during the late Paleocene. From there, early bats dispersed to Africa, forming a Europe-Africa hub from which they later spread to Asia, the Americas and Australia.

Genomes, Fossils and an X Chromosome Clue

The team examined genomes from 103 bat species, including 42 newly generated chromosome-level assemblies, covering all 21 recognized bat families, according to a University College Dublin summary of the paper. Researchers paired those with traits from 44 fossil bat species. In all, 137 researchers from 64 countries took part.

The work also helped resolve long-running disputes about how bat families are related. One obstacle was that early bat lineages appear to have exchanged genes, leaving conflicting signals in different parts of the genome. A region of the X chromosome turned out to preserve an especially clear record, which helped settle relationships that had been disputed for decades.

A key fossil was Vielasia, which the analysis placed on the oldest branch of the bat family tree. Its features point to the ability to echolocate. Dávalos said the analysis shows "the oldest branch of bats already had species that unambiguously echolocated." Based on that tree, she said, echolocation evolved shortly after flight did.

Emma Teeling, a professor at University College Dublin and co-founding director of Bat1K, said that after decades of conflicting findings, "we finally have a robust phylogenetic tree." Other senior authors included David Ray of Texas Tech University, Michael Hiller of the Senckenberg Research Institute in Frankfurt and Sonja Vernes of the University of St Andrews.

Strong Evidence, Not the Final Word

The study is peer-reviewed, but its central conclusion is a statistical inference rather than a direct observation. No one has found a fossil that can be identified as the first bat. Instead, the team used evolutionary and biogeographic models to estimate the most likely place and time of origin based on genomes, fossil traits, and ancient geography.

That distinction matters. The conclusion rests on the fossils known today, and the early bat fossil record remains sparse. A significant new fossil discovery, in Europe or elsewhere, could test or refine the result. The age of the Wyoming skeletons is not in question; the debate is over what such fossils imply about where bats began.

The researchers also computationally reconstructed the genome of the ancestor of all living bats. They say the resource could eventually help scientists study the genes behind many bats' unusual disease resistance and long lifespans, with possible relevance to human research on aging and immunity. Those applications are prospective, and the study did not test any medical treatment. Funding came in part from the European Research Council, Science Foundation Ireland and the Irish Research Council.

A Sturdier Foundation for Bat Research and Conservation

A reliable family tree helps biologists understand which lineages are most distinct and how key traits evolved. The dataset drew on samples collected over decades from remote places, including the tiny bumblebee bat of Thailand and Myanmar and the sucker-footed bats of Madagascar, which use suction cups on their wrists and ankles to cling to small leaves.

Readers who see claims that bats definitively came from Europe should look for the qualifier. The evidence makes Europe the most likely origin based on current data, which is a strong scientific result but not a closed case.

The finding does not change any public guidance on bats. People who find a bat indoors or have direct contact with one should contact local health or wildlife officials rather than handling the animal.

What Readers Want to Know

What did the new bat study find?

The study concludes that bats most likely originated in Europe during the late Paleocene, about 65 to 60 million years ago, then spread to Africa and later to Asia, the Americas and Australia.

Does this prove bats did not originate in North America?

No. It makes Europe the most likely origin based on current genomes and fossils. It is a model-based inference, and new fossil finds could test it.

What about the old bat fossils from Wyoming?

The Wyoming skeletons, about 52 million years old, remain among the oldest bat fossils known. Their age is not disputed; the question is what they say about where bats first evolved.

Did echolocation evolve before or after flight?

The analysis suggests both appeared near the origin of bats, with echolocation evolving shortly after flight. A fossil bat called Vielasia, placed on the oldest branch of the family tree, shows features linked to echolocation.

How large was the study?

It analyzed genomes from 103 bat species, including 42 new chromosome-level assemblies, plus traits from 44 fossil species. The work involved 137 researchers from 64 countries.

Does this change advice about bats near homes?

No. People who find a bat indoors or have direct contact with one should contact local health or wildlife officials and avoid handling it.