This is a widespread and locally common Irish bat. In some summer roosts 500-600 may be found together in the attics of buildings. During winter they hibernate in caves or other dark passages but are difficult to locate as they favour long, narrow cracks and crevices.

The upper fur is greyish-brown, sharply contrasting with the white underfur. The 'tragus' in the ear is long and pointed - more than half the ear length. The best feature is the tail skin. This has a curved edge with a fringe of bristles along the edge. Flight dimensions are: wing span 11in. (28cm); width 31/2in. (9cm).