Mammals see with their eyes, hear with their ears and smell with their nose. But which sense or organ allows them to orient themselves on their migrations, which sometimes go far beyond their local foraging areas and therefore require an extended ability to navigate? Scientific experiments led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) now show that the cornea of the eyes is the location of such an important sense in migrating bats. If the cornea is anaesthetised, the otherwise reliable sense of orientation is disturbed while light detection remains unimpaired.