The Fascinating World of Bats

• The Fascinating World of Bats

Far from being the scary pests that attack people viciously at night as popular movies make them out to be, the bats are friendly creatures which protect us from mosquitoes and pesky insects that damage crops or spread disease. They belong to the mammal group called Chiroptera, and they are the only mammals that fly.

Published by Uma Shankari
July 27, 2013, Category: Biology

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Bats play an important role in many environments around the world. Sadly, many bat species around the world are endangered due to loss and fragmentation of habitat, diminished food supply, destruction of roosts, disease and hunting or killing of bats.

My early memories of bats come from MeenakshiAmman temple at Madurai. As a young girl I would look up to see them perched at every nook and corner on the top ceiling of the entrance gate. I’d hear their flapping wings and would be scared they might swoop down on me. I used to wonder why the place was so smelly.

I grew up, but the fascination remained. I later found that bats, like snakes, have always fascinated people. Westerners, though, saw them as evil, as representing black magic, Devil and Death, and as invoking ghoulish images of a blood-sucking Dracula. Their mystique probably came from being found in dark caves, abandoned buildings, church steeples, and tombs and in being nocturnal animals, active during night. The eeriness of their appearance is heightened when you see them hanging upside down in clusters.

In Asia, especially in China and Indonesia, bats are revered and considered symbols of good fortune!

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Let us understand the vital ecological role the bats play.

• Bats are mammals, the only mammals that actually fly. They live in every continent in the world, except Antarctica. They prefer to live in climates that are warm.

• There are well over 900 recognized species of bats. They are divided into two types – the megabats, which mainly eat fruit, and the microbats, which mainly eat insects. Bats can be as large as a small dog or as small as a bee. There are flying fox bats with wingspans of 2 meters and body weights of 2 kilograms. At the other end of the spectrum, the bumblebee bat weighs only 2 grams!

• Bats are primary predators of night-flying insects and pests. Because they consume quantities of “bugs” such as mosquitoes, bats are a natural form of insect control and play an important role in keeping ecosystems in balance. For instance, one little brown bat can catch 600 mosquitoes or more an hour. They are also pollinators of plants.

• The wings of a bat are actually thin membranes of skin that stretch between the fingers of the front leg and extend to the hind legs and tail. The unique wing structure gives them a great deal of flight maneuverability in catching quick-moving insects. When the bat rests, it folds the wings alongside the body to cover and protect the delicate finger bones and wing membranes.

• Bats are not blind; in fact they can see almost as well as humans. But to fly around and hunt for insects in the dark, they use a remarkable sonar-like high frequency system called echolocation. The bats emit brief sounds of high frequencies (15–200 kHz) through the mouth or nostrils and listen to echoes reflected from prey and objects around them. This enables them to map their surroundings and gauge how near or far the source of sound is.

• Some bats migrate to warmer climates during the winter. But many spend most of the winter hibernating, a state of inactivity in which their bodies have lower temperature and metabolic rate. They use stored fat as fuel and save energy over the colder months when insects are harder to find. They come out of hibernation in summer.

• Male and female bats tend to remain separate in summer. They mate during the autumn. In a process known as delayed fertilization, the females store the sperm in their bodies. Ovulation occurs in the following spring and pregnant females gather together in maternity roosts.  Pregnancy lasts between 6 and 9 weeks. The newborn bats are blind and without fur, and are nursed by their mother until they are 6 weeks old. Young bats begin to fly by the time they are a month old.

• Bats are very sensitive to disturbance during the maternity season and may abandon their young if they are disturbed.

• Most bats do not drink the blood of other animals. 70% of the bats are insectivorous. Only vampire bats, which live in large colonies in Central and South America, feed on the livestock found in abundance in those places. Vampire bats possess specialized infrared sensors on their nose with which they can locate an area where the blood flows close to the skin. Their pointed, blade-like sharp incisors help them drink blood from an animal for more than 30 minutes without waking up or hurting the victims. They also have strong hind legs and a special, elongated and robust thumb to climb around on the prey and to take off after feeding. The saliva of vampire bats contains a substance called draculin, which prevents the victim’s blood from clotting.

• The flying fox, Pteropus Vampyrus, is the world’s largest bat species. Its wingspan reaches a humungous 6–7 feet that makes them look like the real batman. Flying foxes live only in tropical and subtropical areas including Australia and eat primarily fruit and nectar and act as flower pollinators and seed dispersal agents.

Despite bats’ many benefits including pollination and insect control, their populations are declining nearly everywhere. The loss of habitat including forested areas and inappropriate use of pesticides have made them an endangered species. This has resulted in the farmers using more chemicals to control insects, further endangering the bats’ lives and harming the health of humans as well.

Source: http://www.bats.org.uk/