Gene losses allow vampire bats to live solely on a diet of blood

While bats have been closely associated with vampires for centuries, there are actually only three species of bats that drink blood. Most of them eat fruits, insects, nectar and small animals, like frogs and fish, instead. Blood is low in calories, while being rich in iron, protein and little else, making it a terrible, terrible food source. Now, a team of scientists has figured out how and why those vampire bat species are the only mammals that can live solely on a diet of blood. Upon comparing...