The Hummingbird’s Tongue

Researchers analyze minute quantities of blood, DNA, and other substances on a glass surface about the size of your hand. In this realm of microfluidics, suction or pumps are used to move the tiny droplets, but these methods tend to be inefficient. Is there a better way to transport liquids on a miniature scale?

The hummingbird does not waste energy by sucking a flower’s nectar into its mouth. Rather, it takes advantage of the cohesive forces that cause water on a flat surface to bead up and defy gravity. When a hummingbird’s tongue makes contact with nectar, the surface of the liquid forces the bird’s tongue to curl into the shape of a tiny straw, and the nectar is drawn upward. In essence, the hummingbird avoids unnecessary effort by letting the nectar force itself up the “straw” and toward the mouth. During feeding, hummingbirds can refill their tongue with nectar up to 20 times a second!

Note: This “self-assembling siphon” has also been observed in some shorebirds, which drink water in a similar way.