People have been warned of vampire bats that is now feeding on human blood and posing danger to many lives.Despite their terrifying names as 'vampire bats', these creatures were previously onlythought to feed on the blood of birds. But new research shows that vampire bats may live up to their name, as they have been caught feeding on humans for the first time. The worrying prospect could lead to the spread of disease, as vampire bats are known to be major transmitters of rabies.
Vampire bats rely solely on blood as their only food source, but usually get this from wild birds. Researchers from the Federal University of Pernambuco in Brazil set out to look at how the species would behave in a situation of scarcity of birds.
The team analysed 70 faeces samples from a colony of hairy-legged vampire bats, living in the Catimbau National Park in Brazil. To their surprise, they found that three samples contained traces of human blood.
Speaking to New Scientist, Enrico Bernard, lead author of the study, said: 'We were quite surprised.
'This species isn't adapted to feed on the blood of mammals.'
Mammal blood tends to have a thicker, high-protein content than bird blood, making it more difficult for the bats to process. In previous studies, when there is no wild bird blood available, bats have fasted and even starved to death, rather than attempting to try pig or goat blood.
The researchers believe that human intrusion in the national park could be driving the vampire bats to try mammal blood. In their paper, published in Acta Chiropterologica, the researchers wrote: 'The record of humans as prey and the absence of blood from native species may reflect a low availability of wild birds in the study site, reinforcing the impact of human activities on local ecological processes.'
As well as traces of human blood in the faeces, the researchers also found that most of the samples had chicken blood in them.
Mr Bernard said: 'They are adapting to their environment and exploiting the new resources.'
The findings are a cause for concern for people in Brazil, as the bats could spread disease, such as rabies.
In the paper, the researchers added: 'This opens a range of research possibilities on vampire bats in the Caatinga, both on the species' biology and the consequences for public health, considering the potential increase in the transmission of rabies in the region.'
The researchers believe that the bats enter houses through holes in the roof or windows, or target people sleeping outside. They now plan to visit the homes of nearby residents to find out how often they are being bitten, and why.