Movie vampires usually wait until the heroine is asleep before seeking her exposed neck. Not so vampire bats that inhabit Costa Rica and much of the Americas.
The little winged animals usually feed on the lower extremities of cattle and other creatures while the blood sources are awake. So the question is why do the larger blood donors fail to react to the bat’s sharp teeth.
A team from Texas Tech University reports that bat saliva contains substances that numb the bite site or prevent blood clotting. Bats share these chemical traits with another blood-sucker, the leech, they said.
The result of the evening feast by bats is far more significant than a small amount of cow blood. In Costa Rica, the bats have been linked to the spread of rabies in cows and the possibility that humans could be infected, too.
Vampire bats, which are native to the Americas, evolved over the last five million years when insect-eating ancestral bats developed a complex combination of physical and
physiological traits that enabled blood-eating, said the Texas Tech report.
“We identified at least three genes that would be beneficial for blood-eating by producing molecules that interfere with host nervous response and blood coagulation,” said Caleb D. Phillips, an assistant professor and curator of genetic resources.