A comprehensive new study tracing the evolutionary origins of bats indicates that these mammals first appeared in Europe around 65 million years ago. The research, which represents the largest combined genomic and fossil analysis of bats to date, also suggests that echolocation—a defining characteristic of many bat species—emerged early in their evolution, before the diversification of modern bat families.

The study, part of the Bat1K project aimed at sequencing genomes of all living bat species, analyzed genetic data from 103 species across all 21 extant bat families. Researchers employed a variety of genomic comparison methods, including whole genome sequencing and targeted chromosomal analysis, to construct a revised phylogenetic tree illustrating the relationships among different bat lineages. This new evolutionary framework challenges some previous classifications, notably reassigning the sucker-footed bats of Madagascar from groups primarily found in the Neotropics to the superfamily containing the widely distributed vesper bats, which are the most common bats globally. The analysis also positioned the vesper bat superfamily as closely related to the superfamily of sac-winged bats, which had previously been considered a more distant relative.

Fossil evidence was integrated into the study to estimate the timing of bat lineage divergences and migration patterns. While Europe, Africa, North America, and Asia had all been proposed as potential regions for the origin of bats, the new findings favor Europe as the most likely birthplace. From there, bats likely dispersed first into Africa and subsequently across other continents.

A significant point of scientific discussion involves the evolution of flight relative to echolocation in bats. A 2008 study based on a 52-million-year-old fossil suggested that flight evolved prior to echolocation. However, the current study, leveraging a far broader dataset, finds that echolocation likely evolved before the diversification of living bats, although it remains unclear whether echolocation and flight arose simultaneously or sequentially. Nancy Simmons, a co-author of the new study and the 2008 paper, noted that the new evidence brings the debate "back where we were a number of years ago," underscoring that definitive conclusions on the timing of these traits remain elusive.

The research sets a foundation for further investigations into the genetic mechanisms underlying bats’ unique biological features, such as powered flight, echolocation, and longevity. Emma Teeling, a zoologist and director of the Bat1K project, described the study as a “springboard” for ongoing research efforts aimed at uncovering the genes and genetic variants responsible for these remarkable adaptations. Ariadna Morales, an evolutionary biologist involved in the project, emphasized that the findings are “rewriting” the biological history of bats, providing a new evolutionary framework for scientists studying this diverse and widespread group of mammals.