Vampire bats have been running on treadmills for science.

A study has tested how the critters survive on a blood-only diet.

The experiments allowed researchers to observe the special metabolism that sees the bats fuelled by blood consumed shortly before.

The study is published in Biology Letters by The Royal Society Publishing.

A publication release explains: "Blood-sucking insects like Tsetse flies fuel their activity by burning amino acids from their protein-rich blood meals. In contrast, vertebrates are not adept at using amino acids for fuel, instead relying mostly on carbohydrates."

"However, one group of vertebrates has evolved to share a love of eating blood: vampire bats. And, unlike most bats, vampire bats are capable runners, meaning we could study their metabolism within a small treadmill rather than a flight tunnel."

"We found vampire bats can fuel most of their running with amino acids in a blood meal eaten only minutes before, just like some insects."

The study was co-authored by Ken Welch from the University of Toronto Scarborough and Giulia Rossi of McMaster University.

"These findings reiterate how strongly metabolism can be shaped by a specialised diet," the study concludes."