Hovering bats use barbed tongues to snare nectar from flowers.

Credit: CALLY HARPER

Cally Harper and her colleagues at Brown University in Providence, Rhode Island, used a high-speed video camera and post-mortem analyses to understand the mechanics of the eponymous organ of the Pallas's long-tongued bat (Glossophaga soricina). The tongue (pictured) can extend up to 4 centimetres, about twice the length of the bat's head. The researchers found that as bats thrust out their tongues, muscles force blood into rows of tiny bristles that usually lie flat along the tip of the tongue. The bristles become erect in 0.04 seconds, trapping nectar between them as the bat retracts its tongue.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1222726110 (2013)