Vampire legends are rich and varied around the world. Some vampires are said to turn into bats or wolves. Some cast a shadow. Others are killed by holy water or sunlight. Their universal origin is difficult to trace, but there’s one thing vampires have in common. They all crave blood. Why blood? Perhaps it is the oxygen carried by the hemoglobin. Blood feasting is not an uncommon practice in nature and it’s not for the oxygen. Blood is made of more than just red blood cells. It’s chock full of platelets, white blood cells and plasma rich in nutrients like proteins and lipids! Thirsty, anyone?