Greater mouse-eared bat  (Myotis myotis)

Classified as Extinct in the UK. Listed under Appendix II of the Bonn Convention, Annex II of the Berne Convention, Annex II & IV of the EC Habitats Directive and Schedule 5 of the Wildlife and Countryside Act (as amended).

The greater mouse-eared bat is one of the larger European bats and has become extinct in England. Its fur is a medium-brown colour on the upper body, and greyish-white underneath. It has large ears with a very prominent tragus, the organ which is part of the bat’s echolocation system.

This species is found across central Europe and in scattered populations across southern Europe, but is threatened with extinction across the whole of its range. It used to be found in Dorset and Sussex, but was officially declared extinct in Britain in 1990.

Greater mouse-eared bats are usually found around human settlements. They probably used caves as roosting sites, and today they hibernate in both caves and mines. They hunt in forests and adjoining cultivated areas.

This bat preys on larger insects, mainly beetles, which they hunt for about four to five hours after emerging late in the evening. They are known to forage on the ground for some of their insect prey.

Male greater mouse-eared bats are polygamous, and may have a harem of up to five females. The females form large maternity roosts in attics or caves and give birth to one offspring, usually in June. When they leave to feed, females leave their babies in a crèche and there are often several females left to guard the roost. The young bats can fly after three weeks, and become sexually mature at three months.

The greater mouse-eared bat was only discovered in Britain in 1958, and the last specimen was recorded in 1990. It is not clear why it became extinct in Britain although it is known never to have been a common animal.

One possibility is that the nursery roosts of this bat were subject to disturbance and destruction. They are extremely susceptible to the chemicals used to treat timber roofs (as are all bats), and it is possible that this process destroyed their maternity roosts.

As this bat has been extinct in the UK for some years, work on conserving it has concentrated on preparing a plan should it ever re-colonise the British Isles. There are regular surveys of its former sites, and, as a commitment to this species, the greater mouse-eared bat is still listed in the UK Biodiversity Action Plans (UK BAPs).

For more on British bats see the Bat Conservation Trust:
http://www.bats.org.uk/

• Echolocation: detecting objects by reflected sound. Used for orientation and detecting and locating prey by bats and cetacea (whales and dolphins).
• Polygamous: mating with more than one partner in the same season.
• Tragus: a soft cartilaginous projection extending in front of the external opening of the ear. In bats it is thought to aid in the location of prey by generating many echoes, but the precise way in which this works is unknown.