Researchers from the University of California, Berkeley, and partner institutions have published near-complete genomes for eight North American species of mouse-eared bats and found that genes associated with the animals' unusually long lifespans overlap far more than chance with genes governing how they interact with viruses. The study appeared in Nature in late August and represents the most detailed genome assemblies yet built for the genus Myotis.

The finding matters beyond the laboratory because these are the same animals whose populations have collapsed across the eastern United States. Myotis species are among the hardest hit by white-nose syndrome, and the little brown bat that anchored the study's cell work is currently under status review for Endangered Species Act protection.

For households in bat country, which covers most of the lower 48, the immediate relevance is not medical. It is that the biology explaining why these bats live so long is now better documented at the moment their numbers are thinnest, and that the tissue samples driving the work came from live animals captured, biopsied, and released at streams and ponds across the West.

Eight Genomes and One Unexpected Cell Response

Juan Manuel Vazquez began collecting the samples as a Berkeley postdoctoral fellow in 2020, working with undergraduates who set mist nets over Western waterways at night. He now maintains cell cultures from 259 individual bats representing 32 species. The genus he focused on, Myotis, contains about 139 of the roughly 1,511 known bat species and shows an extreme spread of lifespans. A Brandt's myotis banded in Europe was recaptured 50 years later. The black myotis, Myotis nigricans, of South and Central America lives about seven years.

The surprise came in the cell cultures. When Vazquez exposed cells from the little brown bat, the longest-lived species in his North American sample, to a lethal dose of a toxic chemical, the cells did not ramp up genes for DNA repair proteins as expected. They up-regulated genes promoting programmed cell death instead. Vazquez described the response as the literal opposite of what the team anticipated, and compared it to the strategy documented in elephants, another long-lived and cancer-resistant animal: if the cell cannot be saved, kill it.

The genomic screens found something else. Myotis bats show heavy selection on proteins that interact with DNA viruses such as herpes, while most other mammals show strong selection across both DNA and RNA virus-interacting proteins. DNA viral-interacting proteins were strongly enriched for selection in bats, said Peter Sudmant, a Berkeley associate professor of integrative biology and co-senior author, contrasting that pattern with most other mammals. Humans and other primates tend to carry more genes for proteins that engage RNA viruses.

A Genus Under Pressure Across Most of the Country

The little brown bat ranges from Alaskan and Canadian boreal forest south through most of the contiguous United States into central Mexico, and its historical range spans 46 states and the District of Columbia. The Fish and Wildlife Service says the species was once very abundant but has declined severely in eastern North America because of white-nose syndrome, with additional mortality at wind energy facilities. The agency is reviewing its status for possible federal listing.

A close relative in the same genus already carries the strongest protection available. The Service published a final rule in November 2022 reclassifying the northern long-eared bat from threatened to endangered, after hibernacula counts showed declines of 97 to 100 percent across a range covering 37 states, the District of Columbia and eight Canadian provinces.

That is the collision at the center of this story. A research team has documented that Myotis bats evolved an immune and cellular toolkit good enough to keep them healthy for decades while carrying heavy viral loads, and a cold-loving fungus introduced from outside North America has cut through that same group anyway.

Evidence Limits Behind the Longevity Headline

The Nature paper is peer-reviewed, and its genome assemblies are a genuine advance, but the longevity findings are comparative and functional rather than causal. The team identified statistical enrichment of positive selection in gene sets, then tested cell responses in culture. That is not the same as showing that a specific gene extends life in a specific animal, and none of it has been tested in humans.

The cell work rests on primary cultures from a limited set of species, and the toxin exposure experiment measured a response to acute chemical damage rather than natural aging. The researchers frame the overlap between longevity and viral interaction genes as evidence that traits including cancer risk, cellular housekeeping and antiviral response evolved together under pleiotropic selection, meaning the same genetic changes shaped more than one trait at once. That is a hypothesis the data support, not a settled mechanism.

The work was funded by the National Institutes of Health and the National Science Foundation. Co-lead author Elise Lauterbur was at the University of Arizona during the research and is now at the University of Vermont. Other co-authors include David Enard of the University of Arizona and Lucie Etienne of the École Normale Supérieure in Lyon. Vazquez has since moved to Pennsylvania State University, which published its own summary of the findings.

Attics, Bat Houses and the Zoonotic Two-Way Street

The bats in question are neighbors. Little brown bats commonly form maternity colonies in attics, bat houses and other human structures during summer, and roost in caves, mines and tunnels in winter. They eat mosquitoes, midges, caddisflies, moths and small beetles, and are known to live up to 30 years.

That proximity cuts both ways, and the researchers were direct about it. Vazquez noted in a statement released by Berkeley that the mismatch between bat and primate antiviral adaptations may help explain why spillover events have been so damaging, and said fieldwork with bats requires care because pathogens can move in either direction.

The practical guidance for homeowners has not changed and does not come from this study. People who find bats roosting in a structure should contact their state wildlife agency rather than handling the animals, since several Myotis species are protected and handling carries its own risks. Cavers and anyone entering mines should follow decontamination protocols, because human clothing and gear can move the white-nose fungus between sites.

Anyone who encounters a bat in a bedroom or has direct contact with one should call their local health department. That is a rabies exposure question, separate from anything in this research.

Where the Work Goes Next

Sudmant said his lab is now focused on a trade-off in the genomes exposed: the problem of a bat producing proteins that attack viral genomes while protecting its own genome from those same proteins. He is running parallel cell cultures across primate species to test how DNA repair and longevity relate outside bats. Vazquez is continuing the longevity work at Penn State.

On the conservation side, the decision to watch is the Service's pending status review for the little brown bat, which would determine whether the longest-lived bat in North America joins its close relative on the endangered list.

The genomes are now public, and the cell lines exist. The animals they came from are a harder proposition, and nothing in the paper changes that.

What Readers Want to Know

What did the researchers actually find? They built near-complete genomes for eight North American Myotis species and found that genes associated with lifespan overlapped far more than chance with genes involved in viral interactions. Bat cells from the longest-lived species also responded to severe chemical damage by killing the cell rather than repairing it.

Does this mean a treatment for human aging is coming? No. The work is comparative genomics and cell culture in bats. It identifies patterns worth investigating and does not test any intervention in people.

Which bats were studied? Eight species in the genus Myotis, the mouse-eared bats, including the little brown bat. Samples came from animals captured in the Western United States, including Arizona, that were biopsied and released.

Why does this matter for conservation? The same genus is being devastated by white-nose syndrome. The northern long-eared bat is federally endangered, and the little brown bat is under review for listing.

Should I be worried about bats near my house? Bats roosting outdoors or in bat houses pose no routine risk and consume large numbers of flying insects. Direct contact with a bat, or finding one inside a living space, is a reason to call your local health department. Do not handle bats.

Can I do anything to help slow white-nose syndrome? Follow decontamination guidance before and after entering caves or mines, respect seasonal cave closures, and avoid disturbing hibernating colonies, since arousal during winter burns the fat reserves bats need to survive.

When will the little brown bat listing decision come? The Fish and Wildlife Service has not announced a date. The species profile currently lists the status review as ongoing.