The hummingbird micropump

A new study published in the Proceedings of the Royal Society B: Biological Sciences provides evidence that hummingbird tongues act like micropumps when drinking nectar. This finding is in contrast to the long-held belief that their tongues use capillary action to pull in fluids. A team of researchers from the University of Connecticut used high-speed film to capture 18 species of wild hummingbirds as they drank from special transparent feeders. They made sure to mimic wildflowers by developing feeders with similar shapes, volumes and concentrations of nectar as the real thing. What they found was that none of the animals used capillary action. Instead the birds flatten their tongues with their beaks which results in an elastic expansion of two narrow tubes along their tongue. This draws the nectar into the tongue, which then recoils to a cylindrical shape as they draw it into their mouths.

Source:

UConn Today

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