Some bat species seek shelter during the day in the attics of large, mostly historic buildings within human settlements, even though they forage for insects at night in the dark surrounding countryside. This requires daily commuting between brightly lit districts and dark foraging grounds. A team at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) has shown that greater mouse-eared bats (Myotis myotis) – Germany’s largest bats – prefer to use sparsely lit or completely dark areas when commuting through residential areas.