Vampire bats may have been given a raw deal, says Paul Faure, a neuroscientist at McMaster University in Hamilton, Ontario. They may be more treat then trick, he says, citing clinical trials of a drug using bat enzymes which have improved recovery for stroke victims.

"Vampire bats are not blood suckers," Faure told the Toronto Star. "They drink the blood, they don't suck it."

Vampire bats, the only mammals in the world to feed solely on blood, do have razor sharp incisors to inflict a tiny wound on their victims and infrared sensors in their noses to find blood vessels.

Neurologists in North America, Europe and Australia are more interested in what happens next. They believe an enzyme in the bat saliva is the key to helping stroke patients get a much higher recovery rate.

Clinical trials began last year involving more then 400 patients in 80 hospitals worldwide to test the effectiveness of a new clot busting drug, Desmoteplase, which is based on the bat enzyme.

In earlier tests 60 percent of the stroke patients given the drug within three hours recovered. Those who were given traditional treatments had a 22 percent recovery rate.

The current standard drug for stroke victims is tissue plasminogen activator, or tPA will open a clogged artery but is also toxic.