Dracula’s Children
2013 06 26

by Carl Zimmer | Phenomena



Millions of years ago, some bats gave up their old habits of hunting for insects and tried something new: drinking blood. These creatures evolved into today’s vampire bats, and it’s mind-boggling to explore all the ways that they evolved to make the most of their sanguine meal.

A lot of the adaptations are easy enough to see with the naked eye. Vampire bats have Dracula-style teeth, for example, which they use to puncture the tough hide of cows. When they open up a crater-shaped wound, they dip in their long tongue, which contains two straw-shaped ducts that take up the blood.

Finding these prey has led to another remarkable adaptation that you can see–at least if you’re a scientist who studies how vampire bats move. Like other bats, they can fly, but on top of that, they can also walk and, yes, even gallop. Here is a video of a running vampire bat made by Dan Riskin (see this Loom post for details). Of the 1200 or so species of bats, vampire bats are among the very few that can move quickly on the ground.



But vampire bats have many other adaptations for drinking blood that are invisible. They use their combined senses–long-range vision, a sharp sense of smell, acute hearing, and echolocation–to find their victims. In their noses, they even have heat-sensitive pits that detect the heat of warm-blooded animals. Once they land on an animal, they apply those pits to the skin to locate capillaries full of hot blood close to the surface.

When vampire bats dip their tongue into a wound, they don’t just draw out blood. They also put their saliva into their victim. And in this liquid are still more invisible adaptations for a blood-feeding life. Vampire bats, you see, are venomous.

This may sound odd. That’s because we usually think of venom as a chemical an animal sticks in your body to cause you pain or death. But biologists define venom more broadly than that: it’s a secretion produced in a specialized gland in an animal, which is delivered to another animal by inflicting a wound, where it can disrupt its victim’s physiology.

Snake venom, the sort we’re all most familiar with, can disrupt physiology to the point of death. And it does so in several ways–jamming neurons, for example, or causing tissue to rot. But other animals that don’t set out to kill their victims also produce venom. Vampire bats, for example, don’t want eat a whole cow. They just want to take a sip.

Unfortunately, drinking blood has some drawbacks. Vertebrates come equipped with lots of molecules and cells that plug up wounds. As soon as they sense even a tiny tear in a blood vessel, they start making clots to staunch the flow.

Vampire bats use venom to keep the blood flowing. In a new paper with a title worth quoting in full–“Dracula’s Children: Molecular Evolution of Vampire Bat Venom”–an international team of scientists explore the molecules that vampire bats use to subvert blood’s defenses.

What’s most striking about vampire bat venom is how it goes after its victim from so many directions. Blood clots develop through a series of reactions that involve a chain of enzymes. Vampire bats produce different proteins to go after different enzymes in that chain. Platelets, which are cell fragments, also clump around wounds to help heal wounds. Vampire bats make separate compounds that attacks platelets.

[...]

Read the full article at: nationalgeographic.com




Related Articles
Real-Life ’Vampire’ Addicted to Blood, Doctors Claim
"The Vampire Tarot" by Robert M. Place
Serbian village puts out vampire warning, advises to stock up on garlic
Bram Stoker books: How ’Dracula’ created the modern vampire
The Great New England Vampire Panic
15th annual European "Bat Night": For the Love of Bats


Latest News from our Front Page

Recent Israeli Synagogue Attack, a Possible False Flag?
2014 11 21
Dear Friends - I woke up yesterday morning to see a newspaper lying on the kitchen table with the front page proclaiming that five people were slain in an Israeli synagogue after a so-called "Palestinian attack." Some members of the media said that four people were killed, others said five, so it seems like that there was some confusion (or ...
The Michael Brown Shooting, Race Baiting for Political Power and Militarization of the Police
2014 11 21
From Youtube: The evidence clearly shows that Officer Darren Wilson was justified in shooting Michael Brown, so why is this case being hyped by the mainstream media and the leftist political establishment?
Detekt: A New Malware Detection Tool That Can Expose Illegitimate State Surveillance
2014 11 21
Recent years have seen a boom in the adoption of surveillance technology by governments around the world, including spyware that provides its purchasers the unchecked ability to target remote Internet users’ computers, to read their personal emails, listen in on private audio calls, record keystrokes and passwords, and remotely activate their computer’s camera or microphone. EFF, together with Amnesty International, ...
New UK spy chief says tech giants aid terrorism, privacy not ‘absolute right’
2014 11 21
Robert Hannigan, the new head of GCHQ The new head of Britain’s GCHQ, the UK equivalent of the NSA in the U.S., said he believes privacy is not an absolute right and that tech giants must open themselves up to intelligence agencies. “GCHQ is happy to be part of a mature debate on privacy in the digital age,” Hannigan said. “But privacy ...
LOL: Atheist Feminist Pornographer Used as Moral Authority in T-shirt Row
2014 11 21
Dr. Matt Taylor was thrust into the headlines this last week, largely for his lead role in successfully landing a spacecraft on a comet 300 million miles from earth that travels at a speed of 85,000 mph. In short, Taylor and his colleagues pulled off one of the most amazing achievements in contemporary science and space exploration, and in a ...
More News »