Shape Shifter

 

(Photo: Cally Harper)

Tongues can do delightful and astonishing things. I am thinking of the way a frog fires its sticky tongue halfway across the universe to snag a passing insect (see below). Or how an alligator snapping turtle wriggles its tongue like a worm as a dinner invitation to fish. And now the Pallas’s long-tongued bat (Glossophaga sorcina) joins this elite club of astonishing animal tongue artists.

These bats, found from Argentina to northern Mexico, and sometimes into Arizona and New Mexico, have the fastest metabolism ever recorded in a mammal, says a 2007 study in the journal Nature. They burn half their body fat each day, and have to make up for it at night by consuming as much as 150 percent of their body weight in nectar from flowers. And of course, they have to do it on the wing. According to a study published today in the Proceedings of the National Academy of Science, the secret to its success is a remarkable ability to change the shape of its tongue into a hemodynamic—or blood-swollen—“nectar mop.”

When lead author Cally Harper, a doctoral candidate in biomechanics at Brown University in Rhode Island, began her study, specialists already knew that bats of this species have an unusual fringe of hair-like structures around the tip of the tongue.  They assumed these were useful for collecting nectar—but passively, like raking icing off a cake using your fingernails. Biologists also knew that these bats have enlarged blood vessels in their tongues. But they didn’t know what to make of them. Harper had a hunch that the two features might be connected, especially since …  Read the full article here.