Piusa caves yield world’s oldest known Daubenton’s bat

Researchers have identified the world’s oldest known Daubenton’s bat in the Piusa caves, ERR reports. The bat was at least 36 years and seven months old when found, making it the second-oldest bat ever recorded in Europe across all species.

Researchers spotted the bat during a winter count commissioned by the Estonian Environment Agency to track changes in bat numbers at hibernation sites. Piusa caves are surveyed every three years. The discovery was a chance find, said Oliver Kalda, a junior researcher in biodiversity and ecological sustainability at the University of Tartu.

The bat’s ring showed it had been marked during a ringing programme in the late 1980s or early 1990s. Researchers ringed many bats in the Piusa caves to study their loyalty to hibernation sites, survival and age. By checking rings when bats return, researchers can learn how old they are.

Ring numbers can be checked against a database for information on when and where a bat was ringed, its species and age, as well as its weight and measurements. Estonia’s first bat was ringed in 1947. More than 16,000 bats were ringed between 1947 and 1996. In the past decade, about 2,000 have been ringed, though in the last few years the number has been several dozen annually.