Genetic Analysis of Spotted Bats Traces Evolution Across Time

Understanding changes in North American bat populations is critical to measuring risk of extinction from emerging threats such as habitat loss, climate change, white nose syndrome and other disturbances. A study published October 7, 2026, in the open access journal PLOS One by Faith M. Walker at Northern Arizona University, USA, and colleagues describes an innovative research design involving the genetic analysis of ancient, modern, and contemporary biological samples from North American spotted bats.

Globally, bats comprise one-fifth of mammalian diversity, but their elusive behavior can hinder scientific observation. For example, spotted bats (Euderma maculatum) are nocturnal, agile fliers who roost solitarily. In order to better understand spotted bats' population genetic diversity and structure, researchers obtained samples from 121 individual bats from across three separate timeframes across the species range in western North America. These samples included live, captured bats, historical specimens from museum collections collected between 1904 and 1991, contemporary specimens collected between 1994 and 2025, and ancient remains recovered from a northern Arizona cave, radiocarbon dated to 120–2,100 years before present (BP).

The researchers were able to describe the genetic structure, genetic variation and genetic relatedness of spotted bats and identify genetic differences between the northern and southern populations. The study had a few limitations, such as a sample bias – many of the modern specimens originated from a single cave. Future studies are needed to better understand the impacts of specific anthropogenic disturbances on population dispersal and dynamics.

According to the authors, "Our integrative approach across temporal scales highlights the conservation importance of preserving genetically diverse core populations, vulnerable leading-edge populations, and isolated relict lineages. Further knowledge of population structure and genetic diversity across the species' range will promote conservation and management actions for spotted bats".

Faith M. Walker adds: "One of the most important findings of our study is that spotted bats in the southwestern United States harbor the greatest genetic diversity across the species' range, making this region a critical reservoir of evolutionary potential for the species. In contrast, northern populations appear to have lower genetic diversity and may be more vulnerable to future environmental change." 

"Rare and elusive species like the spotted bat can be extremely difficult to study using conventional methods. Genetics allows us to see patterns of connectivity, isolation, and long-term persistence that would otherwise remain hidden, providing information that can directly inform conservation planning."

"One of the most rewarding aspects of this project was bringing together samples collected over more than a century, from museum specimens and ancient cave remains to bats captured in the field today. Each sample represented a small piece of the species' history, and together they allowed us to reconstruct a much broader picture of how spotted bat populations have changed through time."

"Spotted bats are among North America's most mysterious mammals. By combining DNA from ancient, historical, and modern specimens, we were able to trace their evolutionary history across space and time and identify the populations that may be most important to conserve for the future."