By ItsNotMagicItsScience

When the sun goes down and the clouds cloak the moon, the night creatures start to emerge from their hiding places underground. Most, like palm civets, binturongs and owls, are no more harmful to us than the creatures that roam in the daytime. But there are other creatures, darker and more dangerous creatures, which have filled us with fear for hundreds of years.

Dracula may be the most famous of the nightwalkers, closely followed by Twilight’s more huggable Edward Cullen, but almost every culture in the world has its own vampires. They may be human or animal in shape but they all share one thing in common: they want to drink our blood.

There are dozens of animals – mainly insects – that live on blood. Some of them we see everyday, like mosquitoes. Others, like the vampire finch of the Galapagos Islands, exist mainly on exotic TV shows. So, while they’re far from cute, few bloodsuckers can scare the living daylights out of us like the vampire bat.

The vampire bat is one of the few mammals that indulge in the delightful practice of hematophagy, which means they feed on blood. Native to North and South America, you can find vampire bats and their legends, including Peru’s mythical chupacabra from Mexico in the North to Argentina and Chile at the very tip of South America. And while the frighteningly named Hairy-legged Vampire Bat and the more poetic sounding White-winged Vampire Bat usually limit themselves to birds and the occasional goat, the speciality of the Common Vampire Bat is mammals. Including us.

But don’t worry. You’re unlikely to be sucked dry like the victims in the movies, and you probably won’t wake up wanting to chew through your best friend’s neck. The average vampire bat consumes about 30ml of blood during a feed. So, with around 5.6 litres of blood in our body, as unpleasant as the experience is, we’re unlikely to miss it.

What if vampire bats were our friends rather than something to be feared? When a vampire bat chomps down, it releases what is known as an anti-coagulant into your bloodstream. This is a chemical secreted by the animal, in this case in the saliva of the bat, that keeps your blood flowing. Normally, when we have any kind of wound, our bodies go into action to try and stop the blood flowing out, which it does by thickening it, a process called clotting.

But scientists have discovered that the enzyme in bat spit that stops the clotting, called desmoteplase, may actually be good for us. Back in 2003 researchers found that bat spit (it’s easier to say than desmoteplase, plus it’s funnier) could also slow down and reverse the blood clots that many people who have strokes suffer from and that can lead to problems like partial paralysis, speech problems and even brain damage.

Since then, the medical trials have progressed from mice to humans, and now the Ohio State University Medical Center in the USA is about to undergo a nationwide medical trial to see if bat spit really can help people suffering from strokes. At the moment, when you have a stroke (an ischemic stroke rather than a hemorrhagic stroke) our current strain blood thinners have to be used within three hours, otherwise they can actually increase the risk of brain damage. The big problem is that many people are unaware they have had a stroke until much later, so these drugs are only used in quite a small percentage of cases.

Bat spit, on the other hand, doesn’t seem to react with the receptors in the brain that cause the damage, meaning that it can be used later than other blood thinners. Which means that in the future, stroke victims stand a much better chance of making a faster and fuller recovery.

The spooky stuff’s not quite over though: the name they’re going to give the new drug? Draculin. Muahahaha.