There are about 40 vampire bats - rescues from a zoo - living in this colony, says Rob Mies, Organization for Bat Conservation's executive director, in a video statement. Vampire bats are expert blood drinkers, whose teeth are evolved to slice into the skin of cows, pigs and other warm-bodied animals. With saliva full of proteins that keeps blood flowing, rather than coagulating, a full-grown bat can drink up to an ounce of blood at a time.
Despite their sanguinary tastes, vampire bats are social mammals. They'll groom each other, get in squabbles, sniff to say "hello" and beg for food. (If you spot any of these activities on screen, you can let a University of Maryland researcher studying the bats know here.)
Vampire bats rarely bite humans, nor are they a major threat for rabies, says the International Union for the Conservation of Nature. In fact, bats are frequently a force for environmental good - not harmful or spooky.