The northern bat (''Eptesicus nilssonii'') is the most abundant species of

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

in northern Eurasia occurring from France to

Hokkaidō is the second-largest island of Japan and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by railway via the Seikan Tunnel. The ...

and south to Kazakhstan.

Description

The northern bat is dark brown or black with some gold touched at the tip of the hairs in the head and back region. Its nose, ears, tail and wings are black or blackish brown. The coat on the ventral side is yellowish brown. It has short and rounded ears. It body length is with a wing span of , and it weighs depending on the season.

Distribution and habitat

The northern bat is widespread throughout Eurasia, and is the most common bat in the northern part of the continent. It occurs from northern Scandinavia beyond the

Arctic Circle The Arctic Circle is one of the two polar circles, and the northernmost of the five major circle of latitude, circles of latitude as shown on maps of Earth at about 66° 34' N. Its southern counterpart is the Antarctic Circle. The Arctic Circl ...

to northern Italy, and eastern England to northern Japan. It favours forest uplands at elevations of .

Behaviour and ecology

Northern bat colonies have moved as far as over a period of several years. It breeds in late autumn, and the females stores the male sperm over the winter.

Hibernation Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is mos ...

begins in November to December and lasts until April. Females become pregnant in spring and give birth 50–60 days later. In summer, males dwell alone. Females form a colony of 10–80 adults in early summer, which they disband in August, when young bats are able to fly. Winter colonies are often found in houses, and natural or artificial underground habitats.

Hunting

Northern bats are nocturnal and fast flying, adapted to hunting airborne insects using echolocation. For example, northern bats commonly hunt

ghost moth The ghost moth or ghost swift (''Hepialus humuli'') is a moth of the family Hepialidae. It is common throughout Europe, except for the far south-east. Female ghost moths are larger than males, and exhibit sexual dimorphism with their differenc ...

s while the moths are hovering above ground to attract a mate. The species hunts in open spaces at a speed of 5–6 m/s. The sound pulse consists of 10-13 ms in normal foraging habitats, sometimes up to 18 ms of steeply frequency-modulated (FM) component (about 40–30 kHz). The bats send out the pulse approximately once every 200 ms, and the steep FM are used to locate obstacles or targets, allowing them to fly indoors. In high latitude areas, female northern bats fly during daytime because of the short nights, but their foraging peaks after dusk and sometime before dawn. Females select small feeding territories where their food source is abundant, and sometimes can be used by the same individual over a period of years.

Genetics

The northern bat is closely related to the serotine bat (''Eptesicus serotinus''). They are distinguishable by appearance but the genetic difference between the two species is an intraspecific variation.

References

External links

*
Eptesicus nilssonii - Science for Nature Foundation
{{Authority control Mammals of Korea Mammals of Azerbaijan Bats of Asia Bats of Europe Eptesicus Mammals described in 1839