Given everything else that’s currently going on in the world, this is a piece of news that feels fitting, somehow: In a departure from their usual diet, vampire bats have begun feeding on human blood.
There are three species of vampire bats, defined as bats that subsist entirely on the blood of other animals. As Live Science recently explained, all three “feed by puncturing the skin of their prey with sharp incisors and lapping up the flowing blood, mixing it with saliva that prevents their gory meal from coagulating too quickly.” Two of the three species will prey on multiple types of birds and mammals; the third species, Diphylla ecaudata, was previously believed to stick exclusively to birds.
But not anymore, according to a study published last month in the zoology journal Acta Chiropterologica. D. ecaudata bats live in the forests of Brazil, where human activity means that wild birds are growing increasingly scarce — but past research has shown that vampire bats can’t go more than two days or so without feeding, meaning that they must have found some other source of blood as a substitute.
To figure out what that source is, the study authors collected poop samples from a bat colony in northeastern Brazil and analyzed the DNA fragments they contained. Aside from human blood, the bats also appeared to be feasting on chickens — still technically birds, but, as domesticated animals, not a normal part of the vampire bat diet.
As the researchers wrote, these results are bad news for a couple reasons (beyond the obvious one that bats feeding on human blood is the stuff nightmares are made of). For one thing, it’s another piece of evidence that we’re disturbing the vampire bats’ habitat, forcing them to alter their hunting habits by driving out the birds they usually prey on. For another, it raises new concerns about rabies transmission, making the bats’ new feeding patterns a public-health issue as well as an environmental one. If you didn’t already have enough to keep you up at night, these bloodthirsty suckers are here to do their part.