DNA secrets of how vampire bats became bloodthirsty

By Helen Briggs BBC News

19 February 2018

DNA analysis is giving clues to how the vampire bat can survive on blood alone.

The bat can drink up to half its weight in blood a day unlike other relatives, which dine on fruit, nectar or insects.

Blood is low in nutrients and can harbour deadly viruses.

Vampire bats have key differences in genes involved in immunity and food metabolism compared with other bats.

The researchers say the bat's gut microbes are also distinct.

They found evidence of more than 280 types of bacteria in the bat's droppings that would have made most other mammals unwell.

"The data suggests that there is a close evolutionary relationship between the gut microbiome and the genome of the vampire bat for adaptation to sanguivory (feeding exclusively on blood)," said study author, Dr Marie Zepeda Mendoza of the University of Copenhagen in Denmark.

The common vampire bat harbours many genes that have been selected to cope with blood feeding, she added.

Continued  

Rainbow boa preying on a vampire bat in a cave in Ecuador

Date: October 4, 2016

Source: Pensoft Publishers

While snakes are well-known enemies to bats, their preying on the winged mammals has hardly been recorded. Furthermore, no bat as big and heavy as the common vampire, has been described being killed and eaten prior to the present study, published in the open access journal Subterranean Biology.

The study, where scientists, led by Sarah Martin-Solano, Universidad de las Fuerzas Armadas, ESPE, Ecuador, record a rainbow boa catching the bat, is the first known such case to have taken place on a cave's floor. The documented observation serves to confirm that snakes do predate on bats in caves, and is also the first such case known from Ecuador.

Apart from the detailed description, the scientists also provide a film, showing almost in full the event of a rainbow boa catching, killing and swallowing an adult female common vampire bat.

The predation has been observed in a 450-metre-long cave in Tena, Ecuador. There, an adult female common vampire bat, one of the three bat species to feed exclusively on blood, was seen to fly into the cave right over the boa's head and its waiting open jaws, raised some 30-35 centimetres above the ground.

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