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Bats are flying mammals who possess every characteristic sign of this animal class: hairs which entirely cover the body, mammary glands which produce milk for feeding their young till they are capable of hunting by themselves, three auditory ossicles into the middle ear, milk teeth and the ability to keep the
body temperature constant. Arms and legs have been evolving into a perfectly flying organ.
All of the metacarpal bone have been considerably elongating, excluding those of the thumb. This finger, formed by just one phalanx, and the third finger, formed by three phalanges, are very close to each other and they make up the anterior margin of the wings. Only the thumb is short and has a nail: this allows bats to climb by leaning on the wrist joints.
A fragile wing membrane, formed by a connective tissue and elastic fibers which contain the nerves, the muscles and the blood vessels, extends through the fingers of the hands, the feet and the tail. The wings allow bats not only to fly, but also to get rid of the excesses of body heat and partly the carbon dioxide coming from breathing.
The nails of the toes allow bats to attach themselves and a complex mechanism, which is based on the interaction between the weight of the animal and the tendon, ensures them not to keep the muscles
contracted, in order to consume less energy. That is why even dead bats do not instantly fall down but they remain attached!
Bats fly fast and skillfully during twilight and night time without crushing and they are able to catch small insects because, with their larynx, they produce ultrasounds, which are released by the nose and the mouth; they are also capable to analyze the eco that is send back to them and understand if it is an
obstacle or a prey.
In late autumn bats hibernate, reducing their metabolic energy consumption so much that they can survive by feeding themselves on the fat reserves they have been storing during late summer and the first months of autumn. But even during summer they can make their body work in saving conditions and that is when, in early morning, they return to their shelter and they go to sleep, lowering their body temperature.
All bat species are protected by the Bern Convention (1979)and by the Habitat Directive (92/43/CEE); they result particularly protected by national legislation and therefore cannot be hunted (L.157/92) and they are safeguarded by regional legislation on the protection of biodiversity. They are also included in Red Lists as particularly vulnerable and threatened animals: the main threats are represented by habitat modifications and transformations, by the anthropogenic disturbance in the wintering and breeding sites, by the use of
pesticides which poison and kill the main prey, which are the insects.
Bats have a very important role as natural 'controllers' of mosquito population… especially in marshy areas like the Fucecchio marshes!
In the artificial underground environments of the former Cementizia a substantial population of wintering Chiroptera has been settled, thanks to the particular microclimatic conditions. In fact the higher levels have no access except from the basic level, so, during winter, when the outside temperature is at the lowest values of the year, the 'upper floors' have a higher temperature, close to the annual external average, since in this areas the warmer air, which is lighter, tends to rise and therefore stagnate. Poggio alla Guardia is also used by Chiroptera as day shelter during summer, since the temperatures inside are always compatible with their needs.
The family Rhinolophidae includes bats whose snout has a skin appendix called 'nose-leaf', which has a horseshoe shape, different from species to species. Its job is to collect the ultrasounds coming from the nostrils and amplify them like a sort of acoustic funnel. During rest they are always hanging upside down and they cover their body with their wing membranes, while the short tail is folded over the back. A particular body conformation allows them to relax their tendons and muscles of the feet while hanging.
There are 5 species in Italy, all of them typically troglophiles.
THIS ARE THE SPECIES FOUND IN POGGIO ALLA GUARDIA:
Rhinolophus euryale Blassius, 1853- Mediterranean horseshoe bat
Rhinolophus ferrumequinum, (Schreber, 1774)-Greater horseshoe bat
Rhinolophus hipposideros, (Bechstein, 1800)- Lesser horseshoe bat
All of the three species prefer warm areas, partially wooded, even near human settlements at different heights (up to 2000 m for the lesser horseshoe bat and not greater than 1000 m for the euryial horseshoe bat). Breeding colonies and summer colonies settle mainly in buildings, caves and tunnels (the greater
horseshoe bat in tree hollows too); the wintering sites are the caves, the mining tunnels and cellars. They have sedentary habits, making short trips between summer and winter sites.
The greater horseshoe bat is the biggest one in the family Rhinolophidae ; it usually flies slowly and predominantly hunts prey while flying. If it catches a very big insect, it takes it to a quite place, where it can eat it without being disturbed. Usually it does not eat the wings of prey, so you can recognize the feeding sites by the remains of the meals. While in the rest position, upside down and with bent knees, it wraps itself in the wing membrane and only a small stripe on the belly remains uncovered.
The lesser horseshoe bat is the smallest and the most minute bat in the family Rhinolophidae (about four inches long) and it seems very soft, due to the relatively long and flowing fur; it is a strongly gregarious species which forms large colonies in every season and when it hangs down. The body is completely wrapped in its dark wing membrane as in a coat.
The Mediterranean horseshoe bat has intermediate sizes and it is distinguished by the upper appendix of the nasal extension (called saddle) which has a pointed and not rounded apex like the other 2 species have. It usually goes out at dusk and is the first one to go out hunting for insects and, in resting places, it forms mixed colonies with others horseshoe bats. Instead, the greater horseshoe bat generally forms small and single-species groups, where members keep a certain distance. There are also cases of larger and
mixed colonies, with specimens in close mutual contact.
The common bent-wing bat (Miniopterus schreibersii) has instead a regular-shaped snout and the tail is completely or almost completely into the wing membrane. The Schreibers's bat was found in Pieve a Nievole (Kuhl, 1817), which is the only bat belonging to the genus Miniopterus in Europe.
In Italy, the species is widespread throughout the territory. It typically lives in caves and is bound to slightly or not at all anthropized environments, in low or medium altitude areas. It takes shelter in natural or artificial underground cavities; summer and wintering sites can change since they are in different locations.
It has medium sizes, its fur on the abdomen is light-grey while the back one is brown-grey. Its brown ears are very small and show up just a little bit from the hair on the head which is short and curly. It has extremely long and tight wings (the wingspan is 280-305mm long), suitable for fast flight. They generally fly very high, with a rapid flight similar to the one of swallows. It is a gregarious species that forms both single-species and mixed colonies, along with horseshoe bats. Hibernation is discontinuous, not deep and it changes from area to area, although it generally takes place between October and November and March and April.