Vampire bats have a diet that consists only of blood. This diet is so specific that they process their food more like blood-sucking flies than any other mammal known.
Scientists made this discovery by studying common vampire bats (Desmodus rotundus) as they ran on a small treadmill. Running is not uncommon for bats in the wild. When not flying, they can often be seen running on the ground, chasing cows, horses, and other mammals.
In the experiment, researchers monitored the carbon dioxide exhaled by the bats as they ran on a miniature treadmill. Up to 60% of the CO2 produced by the bats came from metabolizing fuels other than carbohydrates and fats. This was surprising as these fuels typically power a mammal’s running.
The bats were actually deriving much of their energy from a high-protein diet of cow blood they had consumed. The gas they exhaled during the exercise contained traces of amino acids, the building blocks of proteins.
Another clue to the bats’ fuel source was the CO ratio2/O2 ratio. This ratio remained constant even as the treadmill pace increased from walking to running. This stability indicated that the bats were not utilizing energy in the typical mammalian way, where gas ratios change with the shift from burning fat to relying on carbohydrates.
The researchers shared these findings in the journal Biology Letters on November 6.
Blood-Powered Running
This discovery suggests that vampire bats can metabolize blood similarly to blood-sucking tsetse flies and some mosquitoes. Ken Welch, an ecophysiologist at the University of Toronto, Canada, believes this is the first instance of this phenomenon in mammals. Welch conducted the experiments with Giulia Rossi, a physiologist from McMaster University.
The basic chemistry behind the blood-based fuel powers of bats is not unusual. “Most mammals can break down amino acids for fuel and other uses,” explains Welch. However, these processes typically occur slowly in the background.
While bears may use amino acids as fuel, Welch notes that this is not the same as the immediate utilization seen in vampire bats after consuming blood. The lack of essential nutrients in the blood diet of vampire bats means their ability to utilize these fuels may weaken over time.
Although relying on amino acids has drawbacks, such as limited availability, vampire bats may be more susceptible to starvation due to their unique diet. As a result, these vampires may need to feed frequently.
Source: www.snexplores.org
