bats and wolves, about the bites that these animals may inflict on humans, and about the terrifying consequences of this, have, from time immemorial featured in folklore from across the world. (For more information on this, see Chapter 3). In societies where people lived close to nature, wolves and bats were greatly feared. Wolves were known to attack humans at night; and bats were possibly even more alarming, since they might fly into a house and bite a sleeping individual without them knowing about it. (It is quite possible to be bitten by a bat at night and not to notice the bite the next morning). Thus, folk tales were full of warnings about these rather mysterious animals who could bring such horror to human beings, merely by biting them, and they became part of the mythology of vampires and werewolves.
Vampires & Animals
There are certain animals whose behaviour – for example, hunting at night, and living off human or animal blood and flesh – has always struck fear into human beings. These include bats, wolves, and owls, who play important roles in European folklore, and who also appear, in different guises and with different meanings, in folklore from other parts of the world.
The vampire bat
Of all these, the common vampire bat is perhaps the most ghoulish. The vampire bat lives on a diet of blood, a habit known as haematophagy. As well as the common vampire bat, there are two other kinds of bat that feed solely on blood: the white-winged vampire bat, and the hairy-legged vampire bat. These bloodsucking bats are mostly found in Latin America, and are especially common in Argentina, Chile, and Brazil, where they feature prominently in folk mythology (see Chapter 3).
As we all know, bats hunt at night, and sleep in the day, often in caves. This nocturnal behaviour accords with the vampire legend, in which the vampire only emerges at night, from the cave-like grave, to strike its victims. The body of the vampire bat in particular is well evolved to locate warm-blooded creatures: it has thermoreceptors on its nose, and these help it to find areas on the skin of its victims, such as the neck, where the blood flows close to the surface. It also has relatively large front teeth that it uses to bite into the victim’s skin. These teeth have no enamel on them, so they are very sharp. If its victim is an animal whose body is covered in fur, the bat’s canine teeth are used to shave off the hair around the area where it makes its incision.
A dinner of blood
The bat’s saliva contains a substance called draculin, isolated by Venezuelan researchers working with the common vampire bat in 1995. This functions as an anticoagulant, which stops the blood from the victim clotting, so that the bat can drink it. (This anticoagulant is extremely strong, and thus has been used in medicine to help patients suffering from blood clotting conditions which may result in heart attacks and strokes.) Contrary to what is generally believed, the vampire bat does not suck blood out of the victim’s wound, but waits until it begins to pour out, and then laps at it.
Bats have an extremely sensitive hearing system, and the vampire bat is able to detect the sound of sleeping victims, which are their main source of nutrition. The common vampire bat seeks out mammals, while the white-winged vampire bat and the hairy-legged vampire bat feed on birds. Once the vampire bat has found its slumbering prey, it flies over to it and lands silently beside it. Using its infrared sensors, it finds a place to bite, and proceeds to tuck in. Its feed can last as long as 20 minutes, and as it feeds its body quickly digests the blood, and it begins to urinate.
The well-fed bat
After its gruesome dinner, the bat weighs considerably more than it did beforehand. A bat weighing 40 grams can amazingly increase its weight to 60; thus it can eat up to half its weight in blood. So its next problem is how to fly off. It does this by