First found in 2008, the 2-inch-long (5-centimeter-long) amphibian is known to live only in southern Vietnamese cloud forests, where it uses webbed fingers and toes to glide from tree to tree. Adults deposit their eggs in water pools in tree trunks, which protects their offspring from predators lurking in rivers and ponds.
"It has absolutely no reason to ever go down on the ground," said study leader Jodi Rowley, an amphibian biologist at the Australian Museum in Sydney.
However, that trick isn't what earned the species its bloodsucking name. Rather, it's the strange curved "fangs" displayed by its tadpoles, which the scientists discovered in 2010.
Frog Fangs Still a Mystery
Tadpoles normally have mouthparts similar to a beak. Instead, vampire tree frog tadpoles have a pair of hard black hooks sticking out from the undersides of their mouths—the first time such fangs have been seen in a frog tadpole. (See more frog pictures.)
Vampire frog tadpoles have small black fangs. Photograph courtesy Jodi Rowley, Australian Museum
The scientists do not yet know what purpose the fangs serve. However, frogs that raise tadpoles in tree-trunk water holes often feed their young by laying unfertilized eggs as meals. The fangs, Rowley speculated, could help in slicing these open.