Bats (All About)
Bats are a much maligned group of mammals. They are not blind. They will not fly into your hair. They will not suck your blood. They are not in league with the devil. Because they can fly so expertly at night without crashing into things, it was thought that they must be in league with the forces of darkness. Science, of course, has revealed the true picture.Read moreRead less
Bats are not blind; they are perfectly well able to see. However as they fly at night and catch aerial prey, they have a special means of detecting this flying prey — echolocation. They emit very high-pitched sound waves which bounce off whatever object they hit and are reflected back to the bat at a slower speed. This is translated as a drop in sound frequency, so the bat can build up a picture of where all the objects are in front of it. These high pitched sounds are above our hearing range (30 –140 kHz) although children can hear some of them, as they can hear higher sounds than adults. Bats catch insects that fly at night.
They are particularly fond of moths, midges and mosquitoes. A small pipistrele bat can catch up to 3000 midges of a night. Each species emits a particular type of ultrasound that allows them to specialise in particular types and sizes of insects so that several species can co-exist in the same area. In Ireland we have ten different bat species — all of which are highly protected under Irish and European law. Ireland holds the largest European populations of the Lesser Horseshoe Bat — a bat that only occurs in limestone areas in Mayo, Galway, Clare, Kerry and Cork. Other species such as the Pipistreles and the Long-eared Bat are widely distributed over the whole country.
Bats go into hibernation in caves or in hollow trees from mid-November till the end of March because there is no insect food available for them to feed on. During hibernation their body temperature drops to as low as 5 degrees Celsius from a normal summer high of 35 to 40 degrees. They need a lot of energy to raise up their temperature again, so if their hibernating roosts are disturbed they may not have enough energy to survive the rest of the winter. In April they wake and move to summer roosts in roof spaces and attics and here their young are born in June or July — one baby per female. These remain in the nursery roost while the mother is out hunting at night and she returns to suckle them. By three weeks of age they can fly and by six weeks they can hunt independently. By the end of August they are weaned. They can live for up to fifteen years.
Things to do
1. Using school books on mammals, the school or local library or indeed the internet, find out the names of all ten bat species that occur in Ireland.
3. Invite an expert into school under the Heritage in School scheme to demonstrate bat detectors.
4. Erect bat boxes in the school grounds. These will provide summer roosts for bats and should be placed high on trees in a hedge or wooded area. A bat box has a slit for an opening rather than a hole as in a bird box.