There are actually three species of vampire bats: Desmodus rotundus, Diphylla ecaudata, and Diaemus youngi. These species are all native to the Americas, mainly central and south (ex: Mexico, Argentina, etc.). Vampire bats front canine teeth are much larger than those of other bats, being made to puncture and tear flesh (to access blood), with smaller rear teeth. Vampire Bat colonies consist of females and offspring with resident males who are the mates (like a bat harem), with other males living in separate area. Vampire bats can only go a couple of days without feeding, and on occasion a bat who hasn't eaten will eat the regurgitated blood from a colony fellow who has fed. Often this sharing of meal is initiated by the bat that has fed.
There are any number of other cool facts about vampire bats, but there's just too much to list here! Definitely check them out (if you haven't already)! :)