Blood Drinking 101

What’s the best way for a vampire to feed?

New Moon, the second installment of the Twilight series, hits theaters today. It features a family of teenage vampires who drink animal blood and who look down on those vampires “weak” enough to prey on humans. The film raises several questions about the logistics—and aesthetics—of blood-drinking.

Where’s the best place to bite a person? Any of the major arteries. If you’re going for efficiency—that is, the fastest blood flow—the best place to sink your fangs is into your victim’s chest. Aim for the aorta, which carries blood out of the heart and is the largest blood vessel of all, up to 1 inch in diameter. (The aorta is located behind the breast plate, so you’d need long, sharp fangs to accomplish this feat.) Such a puncture would likely result in your victim’s death. The next biggest artery is the femoral artery, which runs down the leg and is best accessed in the upper thigh. Again, it’s hard to stem blood loss from the femoral artery, which is roughly the size of an index finger—victims of gunshot wounds to the groin area often die within minutes. The carotid arteries in the neck and the radial arteries in the wrists also offer ample blood flow. If a vampire goes for the neck, he’ll get more blood the lower down he bites, since the common carotid artery splits off into two smaller arteries about halfway up.

If you want your victim to survive, go for his veins. Whereas arteries carry blood from the heart—and have higher blood pressure—veins carry blood to the heart and have lower pressure. It’s therefore easier to patch up a puncture wound to a vein than to an artery. (When you see a wound spurting, that means an artery was hit, whereas bleeding from a vein is smooth and constant.) The most accessible veins are the jugular in the neck and the great saphenous vein that runs just under the skin inside your upper thigh. Although significantly less dangerous than hitting an artery, a puncture wound to a major vein would likely cause profuse bleeding and require significant medical attention. To be extra safe, you might be better off pricking a few capillaries in your prey’s fingers.

How much blood can a vampire drink without killing his prey? About four pints. The average adult has about 10 pints of blood in his or her body. It’s possible to lose up to 15 percent without feeling much of a difference—that’s why donating a pint of blood is no big deal. After losing up to 30 percent, your victim might feel cool and dizzy and his heart rate would go up, but he probably wouldn’t need a blood transfusion. If he loses between 30 percent and 40 percent, his blood pressure will drop, his heart rate will surge, and he’ll go into shock, usually necessitating a transfusion. Upon losing more than 40 percent, he’ll likely die without resuscitation and a generous transfusion. That said, the amount of blood a person can lose and still survive varies widely: For example, a young person can sustain more blood loss than an old man with a weak heart. Speed of bleeding matters, too. If your victim’s losing blood slowly, he can survive a larger loss than if his blood’s coming out all at once.

Does blood taste different, depending on what your victim ate for dinner? No. Human blood tastes the same, pretty much no matter what. Whether you’re Type A, B, AB, or O, blood has a vaguely metallic flavor thanks to the iron contained in hemoglobin. Some people describe the taste as copperlike. That’s not going to change noticeably no matter what your victim ingests. For example, his blood isn’t going to taste sweeter after he’s eaten a few packs of Skittles. (Mosquitoes seem to prefer certain blood types, but that has more to do with the chemicals we secrete than the taste of our blood.) Even alcohol barely alters flavor. Think about it: The legal blood alcohol content limit for driving is 0.08 percent. Even if your victim’s BAC level reached 0.4 percent—enough booze to kill—that’s still less than one-tenth the alcohol content of Smirnoff Ice. The taste of different animals’ blood does vary slightly. Pig blood, for example, is more pungent than duck blood, while goat blood contains hints of the taste of goat meat. These variations affect the taste of blood-based dishes from sausage to soup to pancakes.

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Explainer thanks John Howard of the Spokane County Medical Examiner’s Office, Barbara Rolek, andStephen Stryjewski of Cochon Restaurant.

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