Species of the month – COMMON BENT-WING BAT (Miniopterus schreibersii)

The common bent-wing bat (Miniopterus schreibersii), also called the Schreiber's long-fingered bat and the Schreiber's bat, is one of 35 bat species living in Croatia. Bats are known as the only mammals that can actively fly, thanks to the skin stretched out between the four extended fingers to the shoulders and between the legs. Despite the old wives' tale that bats can get tangled up in one's hair, the facts are quite different. Namely, the bat is able to precisely find its way around, even in complete darkness, thanks to echolocation - a means of orientation in space using sound. Bats release sound signals through their mouth and nose that bounce off of prey or other objects and are relayed back to the bat's ears. The sounds they release have a high frequency and cannot be heard by the human ear.
The common bent-wine bat is a medium sized bat, and its fur can vary in colour from greyish-brown to ashy-brown, with a light grey belly. The relatively small head is marked by the short and triangular ears that are set quite far apart, and by a very short snout. The lifespan of this species is about ten years, even though much older specimens have been recorded.
This species of bat is tied to underground shelters, such as karst caves in lowland and mountainous areas, up to altitudes of 1400 m. The nursing colonies made up of gravid females and females with young are exclusively tied to caves or abandoned mines, and can include up to several thousand females. It is known that up to 2000 individuals of the common bent-wing bat can be attached to a single square metre of ceiling area, as they are often distributed in several layers. The female give birth to one young at the end of spring, and at night when they depart for the hunt, they leave them in these "kindergartens".
Only after sundown does this bat come out of the cave in search of food, in quick and nimble flight. They usually hunt for prey such as moths, mosquito, flies and spiders in open areas, at heights of 10 to 20 m. They feed on many insects that are pests in maintaining biodiversity in the ecosystem.
In the winter months, when the temperatures are low and there are no insects for food, colonies of common bent-wing bat can be found hibernating in caves together with other bat species. During hibernation, which begins in October and lasts until the end of March, all vital functions (beating of the heart, breathing and metabolism) are reduced to a minimum to save energy, and the body temperature is just slightly above the ambient temperature.
Even though this is one of the most abundant bat species in Croatia, the common bent-wing bat is sensitive to disturbances and, especially today, is highly threatened by human activities. Some of the causes of threat of the common bent-wing bat are the loss of cave habitats, excessive use of pesticides that reduce insect numbers, and the fear and prejudice of people stemming from ignorance. This species, the grey long-eared bat (Plecotus austriacus) and the long-fingered bat (Myotis capaccinii) are the most threatened bat species in Croatia. According to the Croatian Red Book of Mammals, they fall into the endangered (EN) category. The reason for this is that more than 50% of nursing colonies known in the mid 20th century have since disappeared, and in the majority of the remaining colonies, the abundance has dropped.
All bats are strictly protected in Croatia under the Nature Protection Act (OG 70/05, 139/08) and the Ordinance on the proclamation of protected and strictly protected wild taxa (OG 7/06, 99/09).

View the remaining species of the month HERE.

Bats - did you know?

• Bats are the only mammals that can actively fly. Some species are exceptionally agile in small spaces, due to the distinctive shape of their wings (short and broad) and can even hover in place like a hummingbird. The long-eared bat can pull spiders out of a web while flying, with virtually no damage to the web at all

• All European bats feed exclusively on insects, many of which are pests, and so bats are very useful in regulating insect abundance.

• Considering that bats are active at night when sight is not of great importance, bats use echolocation, a system for getting around using sound, when hunting and flying. Some species are even able to locate prey no more than 2 mm large in the complete darkness.

• In order to survive the winter, due to low temperatures and a lack of food through an unfavourable part of the year, bats have developed a special adaptation: hibernation. While hibernating, all the vital functions are slowed and the body temperature is only slightly above the ambient temperature. During that time, bats usually hide underground where temperatures are low, but constant.

• The smallest bats, some of which live in Croatia, the lesser horseshoe bat (Rhinolophus hipposideros) and the common pipistrelle (Pipistrelus pipistrelus), weigh only 2 to 4 grams.

• In comparison with other mammals of the same size (e.g. rodents), bats can live very long. Specimens up to 30 years old have been recorded.
All bats in Croatia are strictly protected under the Nature Protection Act.