Bats Use Blood to Reshape Tongue for Feeding

May 6, 2013 — Brown University scientists have found that a species of bat uses blood flow to reshape its tongue while feeding. The quick dynamic action makes the tongue an effective "mop" for nectar and could even inspire new industrial designs. 

(Credit: Cally Harper in the Brainerd-Swartz Lab/Brown University) 

Nectar-feeding bats and busy janitors have at least two things in common: They want to wipe up as much liquid as they can as fast as they can, and they have specific equipment for the job. A study in the Proceedings of the National Academy of Sciences describes the previously undiscovered technology employed by the bat Glossophaga soricina: a tongue tip that uses blood flow to erect scores of little hair-like structures exactly at the right time to slurp up extra nectar from within a flower. 

The bat's "hemodynamic nectar mop," as the paper dubs the tongue tip, features speed and reliability that industrial designers might envy, said lead author Cally Harper, a graduate student in the Department of Ecology and Evolutionary Biology at Brown University. As a matter of what nature can evolve, she said, the tongue tip is surprisingly clever. 

"Typically, hydraulic structures in nature tend to be slow like the tube-feet in starfish," Harper said. "But these bat tongues are extremely rapid because the vascular system that erects the hair-like papillae is embedded within a muscular hydrostat, which is a fancy term for muscular, constant-volume structures like tongues, elephant trunks and squid tentacles." 

In other words, the bat's cylindrical tongue has a mesh of muscle fibers that contract so that the tongue becomes thinner but longer (extending farther into the flower). The discovery reported in the paper is that the same muscle contraction simultaneously squeezes blood into the tiny hair-like papillae. 

Continued: http://www.sciencedaily.com/releases/2013/05/130506181448.htm