Bat Hibernation: In Groups or Individually?

This study focuses on the hibernation behavior of the western barbastelle bat (Barbastella barbastellus) in underground systems in Poland from 2006 to 2011, specifically during the peak hibernation months of December to February. The impact of climate parameters, namely temperature (T), humidity (Rh), and air flow velocity (v), on the clustering behavior of bats during hibernation was investigated. The climate parameters varied within specific ranges: T fluctuated between 6.0 and 12.4 °C, Rh ranged from 56.4 to 91.8%, and v varied from 0.01 to 1.17 m/s. The quantile linear regression method for statistical analysis of the results was employed. This study found that certain combinations of climate parameters influenced the grouping behavior of bats during hibernation. The model structural parameters revealed the following relationships: 1. An increase in the product of T and v led to an increase in the bats’ group size. 2. For pairs of variables such as T and Rh, and Rh and v, an increase in their product resulted in a decrease in the bats’ group size. 3. When considering the product of T, Rh, and v, a decrease in the bats’ group size was also observed.