Myotis myotis
mouse-eared bat

This species is found throughout Eurasia and part of northern Africa. It has gone extinct in the United Kingdom after 1990.

M. myotis primarily inhabit caves and buildings such as churches and castles. They also dwell in relatively open, lightly wooded forests.

M. myotis are relatively large bats, with long ears, overall length 6.5-8.0 cm, broad wingspan 36.5-45.0 cm, and forearm length about 5.7 cm. Adult body weights are about 20-45 g. Females are larger than males.

M. myotis are very similar to M. blythii phisically.

M. myotis are early breeders. Ovulation and fertilization may take place during February mostly, or in October if birth occurs in winter. Gestation period is about 60-70 days. Births take place mostly in April to June, but some were observed in winter. After birth, young M. myotis remain fixed on their mothers for about 2 weeks. Female M. myotis mate again as soon as the young become independent. Females store sperm in the uterus, but eggs are not fertilized until the next spring.

Babies are born with claws on their hind feet and milk teeth. They are blind at birth. The young become independent after 2 months and start to feed on insects. They must accumulate sufficient fat reserves for hibernation.

Life span in Myotis is usually 6 to 7 years, but M. myotis were recorded as 13 years old in the United Kingdom. In wild, some may survive up to 22 years.

M. myotis are nocturnal. They possess a large activity space with a radius of around 10 km. The distance between their summer and winter accommodations can be over 10 km. They usually live in groups and each group can be around 10-100 individuals. They prefer caves or attics, but sometimes also roost in buildings where temperature is not as stable.

They fly relatively low, about 5 to 10 m.

When hibernating, their heart rates drop from 600 to only 18-80 beats per minute.

These bats are opportunistic predators. They primarily feed on ground beetles such as carabids (Carabidae), but also prey on large moths and grass beetles whenever possible. M. myotis prefer feeding in open woodland with ground cover of few grasses. They may have evolved to catch ground beetles on the soil surface. However, they may select alternative preys if primary sources do not meet their requirements. They consume around 25-50% of body weight nightly.

The main factor that causes decline of M. myotis populations may be human disturbance. People both use agrochemicals which poison bats, or disturb caves that causes death at roosts. In addition, large scale agricultural change has reduced areas of open ground and increase grassland, and this also results in reductions in the number of bats.

IUCN status category: Low risk, near threatened.

Red book: vulnerable.

Numbers have declined fast recently and the species has gone extinct in northwestern Europe.

Fossil evidence shows the separation of M. myotis from M. blythii occurred during the Pleistocene.