Five things everyone should know about vampire bats
1. There are no vampire bats in Transylvania. Bram Stoker’s 1897 novel Dracula popularized the connection between Eastern European vampires and bats. But Old World vampire folklore was well established before the discovery of actual vampire bats, all of which reside only in South and Central America. Out of nearly 1,400 bat species, only three are blood feeding, or hematophagous: the common vampire bat (Desmodus rotundus), the hairy-legged vampire bat (Diphylla ecaudata), and the whitewinged vampire bat (Diaemous youngi). Several other bat species with “vampire” in their names, such as the greater false vampire bat (Megaderma lyra) and the spectral bat (Vampyrum spectrum), are actually carnivores that eat frogs, birds, and even other bats.
2. They are highly skilled hunters and use a variety of adaptations to find their food. Vampire bats are the only mammals known to use infrared radiation to locate areas with high blood volume on their target prey, and they have highly sensitive hearing that can differentiate between the breathing patterns of individuals. Because these bats can consume more than half of their own body weight in a single meal, they also have specially adapted stomach linings to allow for urination within two minutes of feeding.
3. Social status matters to vampire bats. Common vampire bats will starve to death if they go three days without food. To hedge their bets, female bats develop strong social bonds via reciprocal blood meal sharing (also known as throwing up in a friend’s mouth). Vampire bats keep track of these “friendships,” and those that share more with others are more likely to receive help in the future. Bats that don’t share are left hungry.
4. Vampire bats are impressive athletes. Using their folded wings as an appendage to propel themselves forward, common vampire bats can run on the ground as a strategy for attacking unsuspecting prey (usually cattle). They are excellent jumpers, capable of leaping into flight by catapulting themselves as high as three feet. Scientists have studied the movements of common vampire bats by analyzing videos of them running on tiny treadmills, and these findings may someday help inspire robot design.
5. These bats don’t suck. Instead, they use their razor-sharp teeth to make an incision in the skin and then proceed to lap up the blood like a kitten. Chemicals in their saliva prevent clotting so the blood of their unsuspecting prey continues to flow freely. Some of these substances, cleverly referred to as “draculin” and “desmoteplase,” have been isolated from bat saliva and are being tested as potential remedies for stroke and heart attack victims.
Amy Wray is a doctoral student in wildlife ecology. Her master’s thesis focused on the feeding habits and pathogens of common vampire bats in Guatemala. Currently, Wray is using next-generation DNA sequencing and other methods to study the diets of insect-eating bats in Wisconsin. The findings will help her assess the extent to which bats feed on agricultural pests and how the spread of diseases such as whitenose syndrome may impact the utility of bats in pest control.