There is not a great deal of legitimate research focused on the science of vampires. However, like Frankenstein, zombies or werewolves, these enduring mythic creatures are rooted in real, observable biological phenomena—taken to extremes, of course.

With the recent DVD release of the first season of The Strain, Guillermo del Toro and Chuck Hogan’s FX series about the outbreak of a monstrous virus unleashed by a race of vampires, and the theatrical launch of Ana Lily Amirpour's stylish and critically acclaimed independent film, A Girl Walks Home Alone At Night, which envisions the vampire as a chador-wearing Iranian woman, Sloan Science and Film spoke with William A. Schutt Jr., Professor of Biology at Long Island University Post, and a research associate at the American Museum of Natural History.

He is also the author of Dark Banquet: Blood and the Curious Lives of Blood Feeding Creatures. Professor Schutt spoke with Science and Film about the nature of blood-seeking creatures, their digestive systems, adaptable traits, and what a vampire might actually look like if it were real.

Sloan Science and Film: First, I'd like to tackle the basics of blood-sucking creatures and how they function.

William Schutt: It’s difficult to make a living feeding on blood, so one of the things that I find intriguing is that they share a number of characteristics, whether you’re talking about leeches, mosquitos, or the largest solely blood-feeding creature in the world, the vampire bat: They’re all small. I think that this has to do with the fact that feeding on blood is difficult, and if you need to find a lot of blood, it gets more difficult. People think that vampire bats are huge creatures, but in reality, they have a ten-inch wingspan.

They’re also stealthy, whether you’re talking about a tick, a mosquito or a leech. These creatures need to get close and tap this resource, but if they’re too loud or make an approach that isn’t stealthy, they’re going to get noticed. They all have sharp teeth that inflict a painless bite, as well. What they inject also has an aesthetic, so that you can’t feel what’s going on. Finally, they all share anti-coagulants in their saliva that prevents blood from clotting.

SSF: How does blood become a nutrient in the same way other animals use food?

WS: Blood is very high in protein. That’s what’s being derived by blood-feeding creatures. A lot of blood-feeding creatures have high-powered kidneys to get rid of the liquid portion of the blood just so they can concentrate on the protein. There’s not a lot of fat in there, so you won’t find a vampire bat in the U.S., where it would have to hibernate because it wouldn’t be able to pack on the amount of fat needed to survive the winter.

SSF: So do vampire bats, for example, feed on anything else besides blood?

WS: They don’t. They get their water requirements from the plasma portion of the blood. They’re really unique in that area, and they can subsist solely on blood and nothing else. They have a very strange biology.

SSF: What’s strange about it?

WS: Their digestive system, for one, is really weird. Our stomach is built for storage and liquefying what we eat. If you look at a vampire bat’s stomach, it looks like an intestine. And like an intestine, its real role is to start absorbing those nutrients and breaking down that blood as quickly as possible. They have relatively few teeth, because they’re not processing their food. And they’ve got a tongue with a groove on the bottom of it, and they apply that tongue to the wound and saliva starts that anti-clotting. They don’t really suck the blood—there’s a groove on the bottom of their tongue that acts like a tube, and that’s how the blood gets from the victim into the vampire bat. It’s a sort of piston-like movement of the tongue that takes place.

SSF: In The Strain, Del Toro’s vampires excrete a pungent ammonia-based spray while they are feeding. Does that come from vampire bats?

WS: Very much the same thing happens with a vampire bat. While they’re processing the blood, they’re peeing while they’re eating. And it would make perfect sense biologically for the vampire excreta to be a “pungent, ammonia-based spray” since ammonia would be a copious nitrogenous waste product of the digestion of blood protein. The same ammonia smell is characteristic of vampire bat urine.

SSF: The Strain’s vampires don’t have fangs, the typical trademark of the vampire, but this long proboscis, which functions as a "stinger." Where is that found in nature?

WS: I can see the biomechanics of that structure. The projectile tongue of a chameleon works very similarly. That’s a fascinating biological structure. What I think is going on in Del Toro’s creation is that it’s not just involved in draining the blood; this is how the virus is transmitted trough these capillary worms. I think it looks really neat, like a cross between a squid’s arm and the tip of a mosquito’s proboscis. It wouldn’t take magic to make it work. The mechanics are there.

SSF: Del Toro’s vampires also have body temperatures that run extremely high. Does that make sense?

WS: In nature, animals heat up during strenuous activity. When they do heat up, their enzymes and molecules have to be able to function at high temperatures, so probably what’s going on in The Strain is that the high temperature is a byproduct of the high activity rate of the capillary worms, and their metabolic activity raises the temperature of the host.

SSF: So it has nothing to do with blood-consumption. Does the body temperature of vampire bats run high?

WS: Vampire bats, and bats in general, fly, and that’s strenuous activity, so that will elevate body their body temperature. Now this is a hypothesis, but one of the reasons we think that bats may carry so many different diseases is the high temperature. It allows them to have a higher disease or pathogen load without getting sick. So the high temperature keeps the viruses from running wild.

SSF: Del Toro’s vampires also develop different interior organs, which most resemble a series of connected sacs. Why do you think this is the case?

WS: With capillaries, there’s a tremendous amount of surface to volume area and you’re able to have a lot of nutrients pass through these structures. When you have a large structure like a bag, the low surface to volume ratio is just efficient enough to support the type of physiology that’s taking place in that host system. There’s no healing; there’s no cell reproduction taking place; it’s just basic maintenance, so it’s a crude circulatory system that seems to work well enough to support delivering nutrients in this host body.

SSF: So, speaking hypothetically, if you were to imagine creating a vampire from scratch, what would it look like?

WS: I don’t see why you have to be hypothetical, because you have all these creatures that essentially do that: it would be small, nocturnal, it would have some enhanced sensory systems, like del Toro’s creatures, where they’re able to detect body heat—vampire bats have thermo-sensory capabilities built into their muzzles. Vision doesn’t do you much good at night. These are all things that I would have if I were designing a vampire.

SSF: Why is being nocturnal so important? Is that just part of the stealthiness?

WS: Think of bed bugs. They’re the perfect example. They’re hiding under the molding, in electrical outlets or in toilet paper rolls during the day and they come out at night, for a very short period of time when it’s dark, and that’s when they feed. o if you’re going to feed on an animal, why not feed when most of them are resting, so that’s at night. Their chances of success increase, and if you’re feeding solely on blood, you have to be successful. For example, a vampire bat can starve in two days if it doesn’t get a blood meal. So therefore, it’s necessary that they are successful.

SSF: How much blood would a 100-pound vampire need to consume to survive?

WS: That’s why we don’t have 100-pound vampires! The system that Del Toro created is different, because his creatures don’t have the nutritional requirements that a normal human body would have. That’s why they have their unique circulatory system, because they don’t need that much nutrition to keep this engine going. Whereas a vampire bat needs to feed on 50% of its body weight per night in order to get the nutrients to survive. So you can see why you wouldn’t want to be large.

SSF: Your book on blood-feeding creatures was published in 2009. Where is your research taking you now?

WS: I just turned in a draft of my next nonfiction book, which is called Eat Me. It’s a natural history of cannibalism. And I just sold a novel about vampires called draculae to Harper Collins.