The largest bat genome and fossil analysis ever undertaken places the origin of bats, and of mammalian flight itself, in Europe about 65 million years ago. For India, home to one of Asia’s richest bat faunas and to recurrent Nipah outbreaks, the new tree is more than an evolutionary curiosity.
A riddle written in wings
Bats are one of evolution’s great success stories and one of its most stubborn puzzles. With roughly 1,500 living species, they account for about one in five mammal species and live on every continent except Antarctica. They are the only mammals capable of powered flight, most navigate by echolocation, many live remarkably long lives for their body size, and several tolerate viruses that devastate other mammals.
Yet their origins have long been obscure. Bat skeletons are small and fragile, and they fossilise poorly. The oldest known bat fossils, from Asia, North America, Europe and Australia, date to the early Eocene, roughly 56 to 52 million years ago, and they already show fully formed wings. Earlier genetic studies variously pointed to Asia, Africa or North America as the cradle of bats.
The Bat1K breakthrough
On 23 September 2026, the journal Nature published the first major results of the Bat1K consortium, an international effort launched in 2017 to sequence the genome of every living bat species. The paper involved 137 researchers from 64 countries.
The team assembled 103 chromosome-level bat genomes, 42 of them newly produced, representing every one of the 21 recognised bat families. They combined this genomic data with anatomical information from 44 fossil bats and modelled the evolution of living and extinct species together. That joint approach, the authors explain, can do what genome-only or fossil-only methods cannot: place the oldest fossil groups on the tree while respecting the genetic evidence, and so estimate when and where bats began.
The answer: bats most likely arose in Europe about 65 million years ago, in the late Palaeocene, shortly after the asteroid impact that ended the age of the dinosaurs. From Europe their early descendants dispersed into Africa, establishing a Europe–Africa hub from which bats later spread into Asia, the Americas and Australia.
Echolocation came early
The study also addresses the chicken-and-egg question of flight and echolocation. The analysis indicates that the oldest branch of bats, the extinct group known as Eochiroptera, already contained species that unambiguously echolocated. Sound-based navigation was therefore part of the bat toolkit from very early on, not a later refinement. The team also placed the fossil genus Vielasia within this ancient clade.
The redrawn tree reshuffles several familiar relationships. The sucker-footed bats of Madagascar, which cling to smooth leaves with suction pads on their wrists and ankles, were previously grouped with New World families; they now sit within the superfamily that includes the vesper bats, the most common bats on Earth. Vesper bats, in turn, turn out to be close relatives of sac-winged bats, once thought distant cousins.
Why genomes, not just bones
Bat1K’s value extends well beyond biogeography. High-quality reference genomes allow researchers to locate the genetic basis of bats’ unusual traits: the immune adaptations that let them carry viruses with little disease, the cellular mechanisms behind their exceptional longevity, and the neural and vocal machinery of echolocation. Those questions connect directly to human medicine, from ageing research to pandemic preparedness.
The Indian dimension
India hosts well over a hundred bat species, from giant flying foxes that roost in temple trees and city avenues to tiny insect-eating bats in caves and abandoned buildings. Their ecological services are substantial and underappreciated: fruit bats pollinate and disperse the seeds of many trees, while insectivorous bats consume enormous numbers of agricultural pests.
Bats also sit at the centre of one of India’s most serious public-health concerns. Nipah virus, which has caused repeated, often fatal outbreaks in Kerala, is carried by Pteropus fruit bats. Understanding how bats tolerate such viruses requires exactly the genomic resources Bat1K is building. A precise evolutionary tree also helps virologists trace how viruses have moved between bat lineages over deep time.
Conservation is the other urgent thread. The Kolar leaf-nosed bat, a critically endangered species, has been recorded from only a handful of caves in Karnataka, where mining and disturbance pose a constant threat. Species with such tiny ranges are precisely those that genome projects risk missing if sampling is not deliberate. India’s participation in the next phases of Bat1K, sequencing its endemic and threatened species, would be both scientifically valuable and a statement of stewardship.
Questions still open
The Europe-origin conclusion rests on the current fossil record, and a single significant discovery elsewhere could shift the picture. Bat fossils from the Indian subcontinent, which was drifting toward Asia during this period, remain sparse; new finds from Indian sedimentary basins could test the model directly. Completing the full catalogue of living species will also require sustained funding, which consortium members acknowledge is far from guaranteed.
Readers should also note the nature of the dating. A figure of 65 million years is a model-based estimate with an uncertainty range, derived from molecular clocks calibrated against fossils; it is not a directly dated specimen. The oldest bat fossils actually in hand remain roughly ten million years younger. The study’s strength is that it reconciles those two lines of evidence more rigorously than any previous attempt, rather than producing an ancestral bat that anyone can hold.
Still, this is a landmark. For the first time, the bat family tree rests on chromosome-level genomes from every family, integrated with the fossil evidence. Bats, it turns out, began their conquest of the night sky in Europe, and their story is far from finished.
