A medium-size specie, big as two fingers put together. The top half of the outside of the ears has a distinct indentation. The fur is long, woolly looking, with a rusty to rufous color. In the Center of France, around the Loire valley, this specie is common, and in some places like Bourges, it's the second in number in winter in caves and underground quarries. Nearly everywhere else in Europe, Geoffroy's bat seems to be considered as a rare specie.