Big brown bat
| Big brown bat | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Great brown bat ( Eptesicus fuscus ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Eptesicus fuscus | ||||||||||||
| ( Palisot de Beauvois , 1796) |
The great brown bat ( Eptesicus fuscus ) is a broad-winged bat that is native to North, Central and South America.
description
The great brown bat is a medium-sized bat with a sturdy body and head, a wide nose and fleshy lips. The total length is 87–138 mm with a weight of 11–23 g. The females are slightly larger than the males (sexual dimorphism ). The ears are short and only barely reach the tip of the nose when you fold them forward. The tragus is broad and slightly sloping forward at the tip. The wings are short and wide. The fur is soft and usually over 10 mm long on the back. The color ranges from light brown to chocolate brown, with the peritoneum lighter than the fur on the back. Eptesicus furinalis differs from other smooth noses in its area of distribution by the large, broad head, the stocky body, the round ears and the short, wide wings. The species also has four upper incisors. It is the only species of broad-winged bat in North America , and the largest in Central and South America .
Way of life
The great brown bat, like most bats, is nocturnal and feeds on insects. It has a large hearing range of 10–45 kHz and uses echolocation for orientation and for hunting. Each night the animals hunt for about 100 minutes and spend the rest of the night in a shelter that is not the same as the sleeping place during the day. Studies have shown that adult animals can eat up to 2.7 g of insects per hour. The flight speed is 13-18 km / h in closed rooms, but can reach up to 33 km / h in open flight. The animals flap their wings more than 9 times per second. From November the animals start to go into hibernation . The wintering places are cool and dry and are mostly located in buildings, mines and caves. The animals usually crawl into narrow crevices individually or in small groups. Before going into hibernation, large brown bats eat their own fat reserves. The average weight before hibernation is 21 g, and by April the animals lose around 25% of this weight. Animals in Cuba do not seem to hibernate, but can go torpor on cooler nights .
Large brown bats can live up to 19 years. Well-known predators include the crimson gray hawk , the great hawk , the weasel , the rat , the domestic cat and the American bullfrog .
The big brown bat was the first bat species in 2006 for whose individuals evidence of a magnetic sense was published.
Reproduction
After the period of hibernation, the females form mother colonies of 5–700 animals, while the males are often found individually or in groups of pure males. In eastern North America, mother colonies are often found in houses, stables, and churches, although colonies are also known to have been found in hollow trees. More than 90% of the females in a colony become pregnant during the mating season. During the first phase of pregnancy, the females build up fat reserves with which they support the growth of the fetus during the later phases of pregnancy. The gestation period of the great brown bat is about 60 days. Each female normally gives birth to only one young per litter in western North America, but two in eastern and Cuba. The birth takes place between May and July. Young animals are born naked, but with their eyes and ears open, and weigh around 20% of a full-grown animal. The pups are suckled for 32-40 days and begin to fly after 18-35 days. 7–10% of young animals die before the end of lactation. If the young are separated from the mother, they utter so-called isolation calls, to which the mother responds with a twittering in the ultrasound range. Mother animals recognize their own young and also take them in if they have fallen down.
distribution and habitat
The great brown bat ranges from Canada to Panama and is also found in the Greater Antilles . In South America, it occurs in Colombia , Venezuela and probably in northwestern Brazil . The species is extinct in the Bahamas . Thanks to its widespread use, the IUCN classifies its population as stable and safe.
Web links
literature
- A. Kurza, RH Baker (1990): Eptesicus fuscus , Mammalian Species 356, pp. 1-10
swell
- ^ Richard A. Holland, Kasper Thorup, Maarten J. Vonhof, William W. Cochran and Martin Wikelski: Bat orientation using Earth's magnetic field. In: Nature. Volume 444, 2006, p. 702, doi: 10.1038 / 444702a .
- ^ Eptesicus fuscus in the IUCN Red List of Threatened Species .