Bats are the only mammals capable of active flight. There are over 1,400 bat species worldwide. They are the second largest order of mammals that comprise about 20% of all classified mammal species worldwide. They are divided into two suborders: Megachiroptera (megabats, fruit bats) and Microchiroptera (small bats). The species in Bulgaria are only from the second group and their food mainly consists of insects such as mosquitoes, moths and beetles. The megabats eat fruit and drink nectar from flowers. Only in Central and South America there can be found three bat species whose food source includes blood from birds and mammals. There are some species that feed on fish and small birds.
Bats have good eyesight. When darkness occurs, they are oriented by a process called echolocation. Some bats live by themselves but most species live together in colonies. For roosts they can use caves, tree hollows and buildings (ceilings and basements). During the winter ,when the temperatures are low and there are no available food resources, bats slow down their metabolism and hibernate.
There are 35 bat species in Europe, 33 of which can be found in Bulgaria. The largest bat in Bulgaria and Europe is the Greater Noctule Bat (Nyctalus lasiopterus) and the smallest is the Common Pipistrelle Bat (Pipistrellus pipistrellus). The world’s largest bat colony is at Bracken Cave and the colony size is between 15 – 20 million bats and the largest bat colony in Bulgaria and the Balkan Peninsula is located in Dyavolskoto garlo cave in Bulgaria and consists of more than 45,000 animals.
Bats are great indicators for a healthy environment. They are extremely sensitive to environmental changes. With their insectivorous diet bats are the main pest controllers on crops.