Mehely's horseshoe bat
Rhinolophus mehelyi
Vasil Popov · Bulgaria
Key facts in one look
- Size
- 10–23 g, wingspan 32–34 cm
- Diet
- Insectivore, mainly moths
- Status in Georgia
- Last recorded in 1964
- Habitat
- Karst caves, scrub and woodland
- Family
- Rhinolophidae
- Conservation
- VU / VU
Mehely's horseshoe bat is Georgia's most elusive bat: it was last seen in the country in 1964 and has not turned up in any survey since 2010. The old records come from Buknari, Mtskheta, Akhmeta, Gelati and the Saguramo reserve. It is a medium-sized horseshoe bat of 10–23 g, with dark "spectacles" around the eyes and an almost white belly. It looks very much like the Mediterranean horseshoe bat, and only a specialist can tell the two apart in the field. If you find a colony of horseshoe bats in a cave, do not disturb it: it could be this very species.
Identification
Mehely's horseshoe bat: how to identify it
A medium-sized horseshoe bat with a horseshoe-shaped leaf of skin on its nose. The back is greyish brown, the belly pure white or nearly so, with a sharp line between them. There is a dark brown patch around or below each eye. The risk of confusing it with the Mediterranean horseshoe bat is high, so only a bat researcher can confirm the species.
Head and body 42–64 mm, tail 21–37 mm, forearm 48–56 mm, weight 10–23 g. The wingspan is 32–34 cm. It is slightly larger than the Mediterranean and Blasius's horseshoe bats, but size alone is not enough to tell them apart.
The fur on the back is thick and greyish brown, with whitish hair bases. The lips are pale; the ears and wing membranes are greyish brown. A dark brown patch around the eyes looks like a pair of spectacles and is much darker than in the Mediterranean horseshoe bat. Colour still varies, so do not rely on it alone.
The most reliable feature is in the noseleaf. Its upper pointed part, the lancet, is slightly notched near the tip, narrow in its upper half and almost parallel-sided. The central "saddle" is naked, rounded and tilted forward, with fully parallel sides. These details can only be seen on a bat held in the hand.
Its echolocation call averages 109 kHz (104–112 kHz), but it overlaps with the lesser and Mediterranean horseshoe bats. A young greater horseshoe bat can also be mistaken for it. So do not catch a bat yourself: identifying it is a job for a specialist.
Mehely's horseshoe bat is a cave bat: it spends the day almost only in caves, sometimes in abandoned mines. In summer it chooses warm karst caves, in winter colder, deeper caves with a stable microclimate. It hunts in Mediterranean scrub and woodland, on dry steppe and pasture, always near water and caves. It occurs from sea level up to about 2000 m. In Georgia it has five records, all from old literature and museum collections. They come from Buknari, Mtskheta, Akhmeta, Gelati and the Saguramo reserve, up to about 870 m above sea level. The last record dates from 1964. Since 2010, 44 new underground sites have been surveyed and the species was found at none of them, although its disappearance has not been confirmed.
Mehely's horseshoe bat feeds mainly on moths. In Spain moths made up 80–90% of its prey, and in Iran about 57–88% in spring. Beetles, flies, lacewings and cockroaches make up the rest. It flies slowly close to the ground or to dense vegetation and catches insects in the air. It probably also picks prey off leaves and the ground.
Mehely's horseshoe bat is nocturnal: it spends the day in a cave and hunts through the night. By day it can become torpid, and in winter it sinks into deeper torpor. In some countries winter colonies reach 5000 animals and summer maternity colonies up to 3000. In the cave they cluster tightly together, and in winter they also gather with other species, such as the greater horseshoe bat and Schreiber's bent-winged bat. It breeds once a year and gives birth to a single young. Mating probably takes place before hibernation. Females choose males with higher-frequency calls, because such a call signals a larger, fitter animal. Females mature only in their third year, males at two. It is mostly sedentary, although movements of more than 90 km have been recorded.
Mehely's horseshoe bat is listed as Vulnerable (VU) on the 2014 Red List of Georgia and received the same category in the 2021 national assessment. Its numbers are falling. It is Vulnerable globally too (VU, 2016): a decline of 30% is expected over three generations, or 27 years. It has already died out in Catalonia in Spain, on Mallorca, in most of Italy and in Croatia. The reasons for its decline are not fully understood. Known threats are disturbance of roosts, cave tourism, destruction of caves and hunting grounds, and in some places collisions with cars. In Georgia, further cave surveys are needed to confirm whether it still occurs.
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Nobody knows. It was last seen in the country in 1964, and wide cave surveys since 2010 have not found it anywhere. The old records come from Buknari, Mtskheta, Akhmeta, Gelati and the Saguramo reserve. Researchers do not rule out that it survives, so the search goes on.
In the field you almost cannot. Mehely's is slightly larger, has a darker patch around the eyes and often a pure white belly. The main difference is in the noseleaf: the lancet is notched near the tip, and the saddle has fully parallel sides. This is only visible on a bat held in the hand, so a bat researcher identifies the species.
It is a medium-sized horseshoe bat. It weighs 10–23 g, its forearm is 48–56 mm and its wingspan 32–34 cm. It is smaller than the greater horseshoe bat and slightly larger than the Mediterranean and Blasius's horseshoe bats.
Mainly moths. In some countries they make up 80–90% of its prey. It also eats beetles, flies and other insects. It hunts in slow flight, close to the ground or to vegetation.
No, it is not venomous and does not attack you. But do not touch any bat with bare hands, because rabies cannot be ruled out by looks. If a bat bites or scratches you, wash the spot with soap and water for at least 15 minutes and see a doctor at once. In an emergency, call 112.
Yes. It is listed as Vulnerable (VU) on the Red List of Georgia and is Vulnerable globally too (VU, 2016). It has already died out in several European countries, and its numbers are falling almost everywhere. Its main threats are disturbance in caves and the destruction of roosts, so keep quiet in a cave where bats live.
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.
