Natterer's bat
Myotis nattereri
soebe · Heidkoppelmoor und Umgebung
Key facts in one look
- Diet
- Insectivore: flies, caddisflies, spiders
- Status in Georgia
- Native; taxonomy unresolved
- Size
- Body 4.4–5.1 cm, weight 7–10 g
- Habitat
- Forest, waterside; tree holes, caves
- Family
- Vespertilionidae
- Conservation
- LC / DD
Natterer's bat (Myotis nattereri) is a medium-sized bat with a greyish-brown back, a white belly and pale wings. Its key feature is a fringe of stiff, curved hairs on the edge of the tail membrane. It flies slowly and nimbly, hovers by foliage and also picks insects off the ground. In Georgia it has been found in Tbilisi, near Ananuri and Telavi, in the Borjomi gorge and near Kutaisi. Recent genetic studies have assigned the Caucasian bats to a separate species, Myotis tschuliensis, so some of the Georgian records may in fact belong to it. If a bat flies into your home, do not catch it with bare hands: open a window and give it time to leave.
Identification
Natterer's bat: how to identify it
A medium-sized myotis with short, dense greyish-brown fur on the back and a whitish-grey belly. A sharp line on the neck separates the two colours. The ears are long and curve backwards, and the ears and wing membranes are smoky grey.
It is medium-sized: the body is 4.4–5.1 cm, the forearm 34–44 mm, the weight 7–10 g and the wingspan 24.5–30 cm. The ears are long and clearly curve backwards.
The most reliable feature is the free edge of the tail membrane: it is wrinkled and fringed with stiff, curved hairs. The cartilage spur that supports the membrane is S-shaped. These features show only on a bat in the hand, so leave identification to a specialist.
Daubenton's bat also has a sharp line between back and belly colours on the neck, but no such fringe on the tail membrane. Geoffroy's bat has a reddish back and a notch on the edge of its ear. Do not catch a bat to identify it: that is a job for specialists.
Colour
The back is greyish-brown, the belly whitish-grey, with a sharp boundary between the two. The ears and wing membranes are smoky grey, and the wings are fairly pale. The desert form, tschuliensis, is paler.
Swatches are illustrative. Do not identify a species by colour alone.
Often confused with
Natterer's bat is mainly a woodland bat: it favours broadleaf forest, parkland and open country with scattered woods, often near water. It occurs from sea level to about 2,000 m. In summer it lives in tree holes, buildings and bat boxes. It spends the winter in caves, tunnels, cellars and crevices, often near the entrance. In Georgia it is considered a partly cave-dwelling species. It has been found in the west near Bakhvi and Kutaisi, in the centre in the Borjomi gorge, and in the east in Tbilisi and near Natakhtari, Avenisi, Ananuri, Telavi, Mughanlo and Sartichala. These are individual records, not a sign that it is common everywhere in these places.
Natterer's bat eats mostly large flies. It also often takes caddisflies, bees and wasps, spiders and harvestmen, and sometimes moths, beetles, bugs and caterpillars. It catches insects in flight, but also hovers by foliage and picks spiders and caterpillars off their threads. It can land on the ground and chase moving insects there. It finds prey by echolocation at 23–115 kHz, loudest at about 53 kHz.
Natterer's bat is sedentary: its summer and winter roosts are usually less than 120 km apart, though a movement of 266 km has been recorded. It leaves to hunt late. It hibernates in winter. It often lives alone or together with other bat species. Mating takes place in the winter roosts. In early summer females gather in nursery colonies of a few dozen animals. After a gestation of 50–60 days they usually have one young, sometimes twins. The young is weaned at 6–7 weeks and breeds the following year. It lives up to 20 years.
Globally Natterer's bat is rated Least Concern (LC, 2023): it is widespread, abundant in many places and its population is stable. In Georgia the 2021 national assessment rates it Data Deficient (DD), and its population trend is unknown. It is threatened by logging and by the destruction of roosts in trees, buildings and underground sites. In Europe it is protected under the Habitats Directive, the Bern Convention and the EUROBATS agreement.
Related guides
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A bat known by this name has been found in Georgia: in Tbilisi and near Natakhtari, Ananuri, Telavi, in the Borjomi gorge, and near Kutaisi and Bakhvi. Recent genetic studies, however, have assigned the Caucasian bats to a separate species, Myotis tschuliensis. Some of the Georgian records may therefore belong to it. DNA studies will give the final answer.
It is medium-sized, with a greyish-brown back and a white belly, and a sharp line between the two colours on the neck. Its ears are long and curve backwards. The key feature is the fringe of stiff hairs on the edge of the tail membrane, but it shows only on a bat in the hand. So do not catch the bat yourself.
It will not attack you, but do not touch it with bare hands. A bat bite can be tiny and easy to miss. Rabies cannot be ruled out by appearance, although most bats people see are not rabid. After a bite or scratch, wash the spot with soap and water for at least 15 minutes and see a doctor; in an emergency, call 112.
Stay calm and take children and pets out of the room. Close the doors to other rooms, open an outside window or door wide and switch off unnecessary lights. Then step back and give it time: a bat usually finds the way out on its own. Do not try to catch a bat in flight.
Mainly large flies, along with caddisflies, spiders and harvestmen. It flies slowly, hovers by foliage and picks prey off leaves and threads. It can also land on the ground and chase an insect there.
Globally it is not threatened: it is rated Least Concern (LC, 2023). In Georgia the 2021 national assessment rates it Data Deficient (DD), which means we do not know enough to judge its condition. In Europe it is protected under the Habitats Directive. Felling trees with holes harms it, so old trees and caves matter to bats.
References
What this profile is based on
Species profiles are compiled from peer-reviewed literature and established biodiversity databases, and are reviewed as new taxonomic and conservation data become available.
Prepared by the Reptiles.ge editorial team from the sources listed here.
