Collecting a vampire bat’s feces is not an easy task.
You must go into the jungle, to the cave where the bats live, then lurk at the entrance at dawn or dusk. As the bats come winging in or out, you catch them in net spread across the cave mouth and transfer them to a cloth bag. Then, you wait.
Sometimes, says M. Lisandra Zepeda Mendoza, who works in bioinformatics and is an author of a recent paper drawing on this raw material, you don’t get what you need. “They get shy,” she says, and one has to let them go before they release a sample.
Luckily, however, Dr. Mendoza’s colleagues at the bat cave mouth were able to collect enough feces that she and other collaborators could sequence the DNA of the bacteria within it. By combining an understanding of what lives in a vampire bat’s gut with the flying mammal’s genome sequence, they have revealed tantalizing insights into how the blood-supping creatures manage to survive on such an unusual food.
Blood, it turns out, is a very difficult thing to live well on. There are almost no carbohydrates — it’s nearly all protein — and few vitamins. Even worse, it’s often laced with viruses. Still, beyond mosquitoes and other insect bloodsuckers we’re more familiar with, a handful of other organisms have somehow managed to do it. As blood-eating mammals, vampire bats, which live in the forests of Mexico and Central and South America, are particularly intriguing.
For the study, which was published Monday in Nature Ecology and Evolution, Dr. Mendoza and colleagues compared their vampire bat genome and microbiome with those of three other bat species: a bat that eats fruit, one that eats insects and one that eats mice, lizards, and other small animals.