White Bats

There are a few species of bat that consume blood exclusively as their diet. This type of diet is referred to as hematophagy, and three species of bat exhibit this behavior. These species include the Common Vampire Bat, the White-winged Vampire Bat, and the Hairy-legged Vampire Bat. The Common Vampire Bat typically consumes the blood of mammals, while the Hairy-legged and White-winged feed on the blood of birds.
Results of eating
Bats’ dung, or guano, is so rich in nutrients, that it is mined from caves, bagged, and used by farmers to fertilize their crops. Also, guano was used in the U.S. Civil War to make gunpowder.