Paris - Vampire bats are astonishingly good runners, thanks to an evolved 
skill to help them sneak up on their prey, says a study published on Thursday in 
the British science weekly Nature.
The blood-sucking species has long 
intrigued scientists.
Bats are the only mammals that can fly but have 
become so specialised at flight that, over the millennia, they have almost lost 
the skill to move on the ground.
The big exception is the vampire bat 
(Desmodus rotundus), which is well known for using terrestrial mobility to creep 
up on a cow, horse or pig, leap on its back and feast on its 
blood.
Whereas its cousins can only shuffle along awkwardly on the 
ground, D. rotundus is the batty equivalent of a breakdancer, able to walk 
forwards, sideways and backwards and then get flying with a single vertical 
jump.
Eager to find out more, animal scientists Daniel Riskin and John 
Hermanson at New York's Cornell University built a special treadmill inside a 
plexiglass cage and put five adult male vampire bats through their paces, filmed 
by a high-speed camera.
The animals used a walking gait at low treadmill 
speeds of up to 0.56 metres per second.
They then broke into a loping 
run, using the forelimbs of their folded-up wings, to propel themselves forward 
when the treadmill was cranked up.
They zipped along at up to 1.14 metres 
per second - warp-factor speeds by bat standards.
Even though vampire 
bats demonstrably have the ability to run, they are rarely seen practising this 
skill in the wild.
The reason, say the scientists: the advent of big 
livestock herds in Central and Southern America, which has made food so 
plentiful that the bats see no point in rushing if they fancy a 
bite.