In a rare technique among mammals, the bats burn proteins from blood, rather than carbs or fat, to power their pursuits of prey, according to a new study

Ask a runner what they eat before a lengthy race and you’ll probably receive a variety of answers. Some will suggest a light meal of fruits or lean protein an hour ahead of a race while others will advise loading up on pasta the night before. For vampire bats, however, it turns out a heaping bowl of amino acid-rich blood will suffice.

Vampire bats lack genes needed for insulin secretion, so instead they rely on quickly metabolising amino acids found in their blood meal

Unlike most vertebrates, which rely on carbohydrates for energy, vampire bats have evolved a remarkable ability to burn amino acids from blood. In this study, the bats were fed a blood meal containing labeled carbon atoms. By tracking the carbon isotopes ...

To work out where bats were getting their energy, the animals were fed a meal of cow’s blood roughly eight minutes before being placed in the centre of the treadmill chamber. Most bats consumed blood that had one of two amino acids (either leucine or glycine) chemically labelled beforehand. Three were kept as controls and fed unlabelled blood.