Alcathoe whiskered bat
Myotis alcathoe
Yuzefovich Alexander · Gorod Novorossiysk
Key facts in one look
- Diet
- Insectivore: small flies, moths
- Status in Georgia
- Native; known since 2023
- Size
- Body about 4 cm, weight 3.3–5.5 g
- Habitat
- Old damp broadleaf woodland
- Family
- Vespertilionidae
- Conservation
- DD / LC
The Alcathoe whiskered bat (Myotis alcathoe) is the smallest Myotis bat in Europe: its body is about 4 cm long, its wingspan about 20 cm and its weight 3.3–5.5 g. Scientists described it only in 2001, because it looks so much like the whiskered bat and Brandt's bat. It lives in old, damp broadleaf woodland near streams and spends the day high up in tree holes. Twenty-five records are known from Georgia, and its presence in the country was first published in 2023. If a bat flies into your home, do not catch it with bare hands: open a window and give it time to leave.
Identification
Alcathoe whiskered bat: how to identify it
A very small, brownish bat with a pinkish face and short ears. It belongs to the whiskered bat group, whose members look very much alike. Adults stand out by their brown fur, but a young one cannot be reliably identified by its looks.
Size: the forearm is 30.8–34.6 mm, the body about 4 cm, the wingspan about 20 cm and the weight 3.3–5.5 g. It is the smallest Myotis bat in Europe.
The back is brown, with a reddish tone in older animals, and the belly slightly paler, greyish-brown. The face and upper lip are reddish-pink, not dark brown or black as in the whiskered bat. The inner side of the ear is white at the base.
The ear, the small flap inside it (the tragus), the foot and the thumb are small. The tragus reaches up to the notch on the edge of the ear, while the whiskered and Brandt's bats have a longer one. These features can be seen only on a bat held in the hand.
The whiskered bat, Brandt's bat and David's myotis look very much like it and sometimes interbreed with it. Only genetic analysis or a recording of its echolocation call settles the species: the Alcathoe whiskered bat's call is the highest of any European Myotis, falling from about 120 kHz to 43–46 kHz. Do not catch a bat to identify it: that is a job for specialists.
Colour
The back is brown, with a reddish tone in older animals, and the belly slightly paler, greyish-brown. The hairs on the back are 6–8 mm long, dark at the base and brown at the tip. The face and upper lip are reddish-pink and the wings brown. Young animals are greyer brown.
Swatches are illustrative. Do not identify a species by colour alone.
The Alcathoe whiskered bat is a bat of old, damp broadleaf woodland. It prefers ravines and riverside forest along streams, with many dead and decaying trees. In southern Europe it lives mostly in mountains, and in places it reaches 2,000 m. It spends the day high up in tree holes, often in old oaks, a habit that is unusual among European bats. Its range runs from Portugal and England to Sweden, the Balkans and the Caucasus. The population on the Russian Black Sea coast was described as a separate subspecies, Myotis alcathoe circassicus, in 2016, and it may be more widespread in the Caucasus. Twenty-five records are known from Georgia.
The Alcathoe whiskered bat feeds on small insects. In one study its food was mostly small midge-like flies, along with small moths, caddisflies, lacewings and spiders. Elsewhere, in eastern Slovakia, moths dominated, together with ants and midge-like flies. The spiders show that it also picks prey off leaves. It hunts mainly high in the tree canopy and over water, often in dense vegetation.
The Alcathoe whiskered bat lives in small groups. A summer roost may hold up to 80 bats, while autumn groups are smaller. It does not travel far to feed: three radio-tracked bats moved only 800–1,440 m from their roosts. Some spend the winter in caves, though it may also hibernate in tree holes. In late summer bats gather at cave entrances; in southern Poland this swarming lasts from late July to mid-September. There it often interbreeds with whiskered and Brandt's bats. Pregnant females are found until June, and young appear from July to September. Held in the hand, an Alcathoe whiskered bat is calmer than a whiskered or Brandt's bat.
Globally there are not enough data to assess the Alcathoe whiskered bat (DD, 2016). It is a poorly known species with narrow needs and a patchy range, so it does not easily settle new places. Threats include the felling of old forests and the building of reservoirs: two of its sites in Greece have already been destroyed. In Germany it is Critically Endangered (CR, 2009), and in Catalonia Endangered (EN). In Georgia the 2021 national assessment rates it Least Concern (LC), with a stable population. Keeping old trees with holes and riverside forests is the key to its survival.
Related guides
Continue with related pages
Yes. Twenty-five records are known from Georgia, and its presence in the country was first published in 2023. It used to be lumped with the other whiskered bats, so it went unnoticed for a long time. Which subspecies the Caucasus population belongs to still needs study.
It is hard by eye. An adult has brown fur and a reddish-pink face, while the whiskered bat has a dark, almost black face. It is also smaller, with a small ear, tragus and foot. Young ones cannot be told apart by their looks, so a firm answer comes from genetic analysis or a recording of the echolocation call.
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.
Small insects. It catches mainly midge-like flies and small moths, and sometimes caddisflies and spiders. It hunts in the tree canopy and over water. The spiders mean that it also picks prey off leaves.
Globally there are not enough data to assess it (DD, 2016). Georgia's 2021 national assessment rates it Least Concern (LC). In some European countries, such as Germany, it is Critically Endangered. What it needs most is old trees with holes left standing.
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.
