Study reports spotted bats in US Southwest have greatest genetic diversity

A study published on 7 October 2026 in the journal PLOS One describes genetic analysis of ancient, historical and modern samples from North American spotted bats. The study is by Faith M. Walker of Northern Arizona University and colleagues. The researchers obtained samples from 121 individual bats across three separate time frames and across the species' range in western North America.

The samples included live captured bats and historical specimens from museum collections collected between 1904 and 1991. They also included contemporary specimens collected between 1994 and 2025, plus six ancient specimens recovered from a northern Arizona cave. According to the study, the ancient specimens had conventional radiocarbon ages ranging from approximately 120 to 2,100 years BP, meaning before AD 1950.

The researchers reported that they described the genetic structure, variation and relatedness of spotted bats, and identified genetic differences between northern and southern populations. Walker said spotted bats in the southwestern United States harbor the greatest genetic diversity across the species' range, making the region what she called a critical reservoir of evolutionary potential. She said northern populations appear to have lower genetic diversity and may be more vulnerable to future environmental change.

Walker said rare and elusive species like the spotted bat can be extremely difficult to study using conventional methods, and that genetics allows researchers to see patterns of connectivity, isolation and long-term persistence that would otherwise remain hidden. She said one of the most rewarding aspects of the project was bringing together samples collected over more than a century. The authors wrote: "Our integrative approach across temporal scales highlights the conservation importance of preserving genetically diverse core populations, vulnerable leading-edge populations and isolated relict lineages."

The study listed limitations, including sampling bias, noting that many of the modern specimens originated from a single cave. The authors stated that future studies are needed to better understand the impacts of specific anthropogenic, or human-caused, disturbances on population dispersal and dynamics.