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Life in the Forest

Life in the River

The Insect World

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Bat Conservation International

Bats

Bats are one of the world's most common mammals. There are over 1,000 types of bat spread out all over the world, making up about a quarter of all mammal species.

Bats are probably the most undeservedly maligned creatures on earth. Because most bats only come out at night, and because of their strange (sometimes grotesque) looks, they have acquired a reputation for being evil and dangerous. The truth is that almost all bats are harmless. In fact, in tropical rainforests all over the world, bats play a vital role in the forest ecology by consuming insects and by disbursing seeds and pollinating plants. About 20 types of trees and shrubs are wholly or partially dependent on bats for the pollination of their flowers.

Bats are usually pictured as living in caves or in the attics of old houses, but bats in the forest often roost in the upper branches of trees. Unlike birds, they roost hanging upside down. Most bats eat insects and fruits, although some species can also detect fish swimming close to the surface of a pond, and can swoop down to grab a fresh fish meal. Because most bats only come out at night, when it is difficult to see, most bats use echo location to find out about the world around them. This means that the bat lets out a high-pitched squeak (so high that humans can't hear it) which bounces off objects and echos back to the bat. If the bat receives an echo, they know that there is something in their path, so they fly to avoid it. This is the same method now used in modern radar and sonar equipment to locate airplanes, submarines, and ships.

Part of the bat's bad reputation is due to its nightime flying habits. When staying in the Amazon rainforest it was quite common to see bats zooming back and forth through the night sky in search of insects. This can be very unnerving if you've never encountered bats before. Because it is nightime you never get to see the bat clearly – you only see it as a fast-moving shadow, hear the flapping of its wings, or occasionally see its outline silhouetted against a nearby light. These bats often fly close to humans, giving the impression that the bat is about to fly into you – but this rarely, if ever, happens.

Although most bats are harmless, there is one kind of bat that visitors to South America need to watch out for – the vampire bat.

Vampire Bats

In Europe there have always been legends of vampires – monsters which drink blood, and often transform themselves into bats to fly through the night sky in search of their next victim. Today we know that these ancient legends are fantasy, and vampires don't really exist. However, there is a species of bat living in South America whose strange feeding habits make it look very much like the old vampire legend.

The vampire bat drinks blood. Although you won't get turned into a vampire if it bites you, it is still very dangerous because of the risk of catching diseases such as rabies. Vampire bats are the only mammals whose diet consists entirely of blood. However, unlike the bats described in the old european legends, vampire bats are very small – full-sized adults measure only 9 cm long.

Like most bats, vampire bats come out at night. They fly in search of a victim to provide their night's meal – usually preying sleeping farm animals, large mammals, and even people. The victims are usually asleep, so don't notice the bat as it gets close to them. The bat will usually land somewhere nearby its victim, then slowly waddle up alongside, before using its very sharp teeth to make a small cut into the victim's skin. The bat then squats on the ground, and laps up the blood as it slowly trickles from the cut. A substance in the bat's saliva stops the victim's blood from clotting, helping ensure that the bat gets a full meal. Within 15 minutes, the bat can drink more than its own body weight in blood – sometimes drinking so much it is difficult for them to fly home afterwards. It needs to consume large qualities because blood is mostly water, low in real nutrients.

Most victims never notice that the bat is there. They just continue to sleep peacefully while the bat feeds. When people get attacked, the only evidence that a vampire bat has visited is usually the discovery of a small cut and blood-soaked sheets the next morning. And if you've been very unlucky, the next sign may be a case of paralytic rabies which may develop three weeks later.

Vampire bats will return night after night to feed on the same victim if it is a covenient one. And they have even been known to move their roosts closer to their victims so as to avoid a long flight home afterwards. If a vampire bat doesn't feed for several nights in a row it will die of starvation. To prevent this happening, other bats regurgitate blood into the mouths of starving family members – thus ensuring other bats' survival.