How do vampire bats suck blood?

Vampire bats do not actually suck blood. They lap it up like a dog drinking water from a bowl. To begin feeding, the bat first must prick the animal with its two large front teeth, often in the foot or leg of a sleeping mammal or bird. An anticoagulant in the vampire's saliva causes the blood to flow without clotting, allowing the bat to lick up its nutritious, protein-filled diet. Vampires take only 2 tablespoons of blood while the host animal continues to sleep. There are just three species of vampire bats in the world and they all live in Latin America. They are very gentle creatures and will adopt orphans and regurgitate and share food for a member of the colony who could not find a meal the night before. The anticoagulant from these bats' saliva has been synthesized and is now used in medication for human heart patients, showing that even vampire bats can be helpful to humans. However, when these bats feed on livestock, they can spread diseases and must be controlled.  more