The Blood-Thirsty Lifestyle of the Common Vampire Bat

The common vampire bat, Desmodus rotundus, is indeed the most common of the three species of true vampire bats: D. rotundus, Diphylla ecaudata and Diaemus youngi. True vampire bats are the only mammals that are entirely hematophagous (eat blood). While D. ecaudata and D. youngi only feed on avian blood, D. rotundus is more of a generalist and feeds on the blood of reptiles, birds, cattle and occasionally humans (Greenhall et al., 1983). Hence the common vampire is the only vampire species that comes into conflict with humans, causing economic damage by feeding on livestock and spreading disease between people and animals, giving vampires a bad name. In this article we put aside the issues with this species as a pest to tell you about the interesting adaptations and behavioural characteristics of the common vampire you may not know about.

There are several hypotheses to explain the evolution of blood feeding behaviour: for example, that they initially fed on insects attracted to wounds of animals or were feeding on ectoparasites of other animals. Whatever the cause, bat phylogeny studies show that the three species share a recent common ancestor, which indicates that blood feeding habits only evolved once (Wetterer et al., 2000).

D. rotundus has many specialised anatomical and physiological features adapted for it’s distinctive feeding habits: firstly, they have large, blade-like canines and procumbent, sickle-shaped upper central incisors (Davis et al., 2010; see above image). Secondly, their mouths have specialised salivary glands that make several types of anticoagulants to prevent blood clot formation. There is one anticoagulant that someone with a sense of humour named draculin (Fernandez et al., 1999).

Additionally, vampire bats have special pit organs around their noses which are loaded with thermoreceptors. These detect infra-red radiation and help the bat locate hotspots on warm-blooded prey, where there are lots of blood vessels close to the surface (Gracheva et al., 2011). Hence, they can detect warm blood running through their victim’s veins from meters away.

D. rotundus tend to feed on the same individual over consecutive nights, using passive-hearing they are able recognise individuals by their breathing sounds (Gröger and Wiegrebe, 2006). This species also shows a high degree of encephalisation (that is, a well-developed brain), which indicates that it’s specialised feeding habits demand high levels of cognition (Greenhall et al., 1983).

Also available in ginger – this adult male is the less common orange morph

Common vampire bats are also remarkably social: they live in groups that are maintained through many years. If a bat is unsuccessful in feeding, other bats from the colony will regurgitate blood to share meals with their friends (Wilkinson, 1984). Feeding other bats’ pups or orphaned pups has also been reported (Wilkinson, 1984).

In summary, the common vampire bat is a very interesting species that has evolved to be a highly specialised and effective hunter, although often to the detriment of many Latin American farmers.

In Belize and other central American countries there are methods of control available from local authorities for dealing with vampires when they come into conflict with farmers. Many people take matters into their own hands by killing roosting bats, however the random killing of bats in retribution for damaged livestock is more likely to affect many other benign species than target vampires. We are currently preparing a guide for dealing with problem bats, this will cover how best to control vampires and will soon be available from the Resources section of this website.

References

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