Bats have long been associated with Halloween, but the connection is by far less ominous than some would suspect. In Halloween's ancient origins, people would gather together around giant bonfires to ward off evil spirits. Attracted to the warmth and bright light of these fires were many small flying insects, natural food for hungry bats. People saw the bats flickering in and out of the firelight during the festivals and they became a feature of Halloween lore.
The link between the bat and Halloween became strengthened with the discovery of the Vampire Bat in the 17th century. Tales of bats that drank blood had circulated throughout Europe for centuries before, but it wasn't until the Spanish exploration of Central and South America that there was physical proof. It was a natural association for a dark holiday, a creature that lapse the life blood of it's prey in the dark of night. ^_^