Vampire Bat

Vampire bats are active only during the darkest periods of the night. It is the time when they are most likely to avoid being caught by such nocturnal predators as owls. Also, the domestic animals on which the bats feed are often sleeping, and so are easier to approach undetected.

To help them find their prey in the dark, most bat species have developed a remarkable navigation system called echolocation. To understand how echolocation works, imagine an "echo canyon." If you stand on the edge of a canyon and shout "hello," you'll hear your own voice coming back to you an instant later.

The vampire bat's ability to reproduce is limited by its need to remain light enough to fly. It gives birth to a single offspring after a gestation period of 6-8 months. Vampire bats mate year-round. Mating takes place while roosting upside down in the security of a cave. A single young is then born some 6-8 months later.

The vampire bat feeds on the blood of animals. Cows, pigs, and horses are its favorite hosts. The bat will usually choose the most docile or isolated animal in the herd on which to feed. Using its chisel like incisor teeth, the bat makes a small cut in the animal's skin. It usually chooses a fleshy area, like the shoulder or neck, where the blood vessels are closer to the skin's surface. The bat then drinks the blood that flows from the wound. Chemicals in the bat's saliva keep the blood flowing for the 2-3 minutes that the bat feeds. Often two or three bats will feed from the same wound. In most instances, the host animal suffers no ill effects from the loss of blood, although if too many bats feed on the same animal, it may be severely weakened.