October 31, 2010
October 31 - Desmodus rotundus
The common vampire bat, Desmodus rotundus, seemed like a good parasite to feature on Halloween. These mammals derive all of their nutrition from the blood of other mammals, usually cattle, but sometimes other livestock and even sleeping humans. They sneak up on their hosts using a very quiet hopping motion and then slice open the skin with razor-sharp teeth, lapping up the blood that spills out. Vampire bats can only survive a few days without feeding, but have evolved a social behavior known as reciprocal altruism where a bat that feeds successfully one night may regurgitate some of its meal to a hungry roostmate. Later, the recipient may be the lucky one and return the favor to this donor. Vampire bats can be found in many places throughout the neotropics, but have sometimes been subjects of eradication campaigns because of the fear of rabies that they can spread.