Leisler's bats were formerly known as hairy-armed bats, due to the long hair around the back and shoulders.

Life span
The maximum recorded age is 9 years, but it is likely that they live for longer.

Statistics
Body length: 4.8-6.8cm, Wingspan: 2.6-3.2cm, Weight: 11-20g.

Physical description
Leisler's bats have short black-brown fur, which is rufous-coloured on the upper-side and yellow-brown on the underside. The face, ears and wing membranes are black-brown.

Distribution
Leisler's bats are distributed nearly all over Europe, although they are absent from Scandinavia, Portugal, and rare in Spain and Italy. They are common and widespread in Ireland. They are also found in parts of Asia.

Habitat
They are primarily woodland bats, but also inhabit parkland and urban areas.

Diet
Leisler's bats emerge shortly after sunset and feed on flying insects, such as moths and beetles.

Behaviour
In the summer, they roost in buildings, bat boxes and tree holes, sometimes with noctules. They hibernate in tree holes and buildings from April to September.

Reproduction
The mating season starts at the end of August, where the male has a defended mating roost and a harem of about nine females. The young are born in mid-June and are weaned after 7-8 weeks.

Conservation status
Leisler's bats are listed as Lower Risk by the IUCN.