This particular species of bats is called "rotundus", from the family "Desmodontidae". They can usually be found around Central and South America, in Mexico, south to Chile and Argentina(see map lower on this page). They are about 2' 3/4" long, their wingspan is 8", and they weight 1 ounce. All in all, they look like ordinary bats. They recognize each other through voice, and smell. These vampire bats live in caves, trees, and buildings. They each require about 2 tablespoons of blood every day. Vampire bats are very agile on the ground. They usually approach the prey on the ground. Heat sensors on the nose helps them locate a vein close to the skin. The incisor teeth make a quick cut. There is an ingredient in the bat's saliva that prevents clotting. It may take 20 minutes to complete its meal. There is also an anesthetic in the saliva that reduces the likelihood of its victim being irritated by the initial bite