Hairy-Legged Vampire Bats Feast on Human Blood

Now, there's a headline that can induce nightmares. There are three species of vampire bat (that we know of), and only one of them, the common vampire bat (Desmodus rotundus), is known to drink the blood of mammals -mostly livestock. The white-winged vampire bat (Diaemus youngi) and the hairy-legged vampire bat (Diphylla ecaudata) target birds for their blood. At least until now. Hairy-legged vampire bats have been drinking human blood in Brazil. That shocked scientists who know how chemically different bird blood and mammal blood is.

As Sandrine Ceurstemont reports for New Scientist, previous experiments have shown that when only pig and goat blood was made available to bats that were used to bird blood, many of them opted to fast rather than diversify their diet - and sometimes even starved to death.
But when Bernard and his team investigated the diets of a colony of hairy-legged vampire bats in the Caatinga dry forests of northeastern Brazil, they found something strange.
Genetic analysis of 15 faecal samples contained bird DNA as expected, but 3 of those samples contained a mixture of human and bird DNA - evidence that these particular individuals had been feeding on both.

This switch in diet could be due to the depletion of some wild bird species, plus farmers locking up their chickens at night. The implications are frightening, as bats have been known to spread hantavirus. Read more about the research that led to this discovery at Science Alert.