Hummingbirds are master acrobats, able to hover and drink simultaneously before flitting off to the next flower. At first glance, you might expect that their tongues are simply tiny straws that use surface tension and capillary action to draw up nectar. But it turns out that process is just too slow for the fast-paced birds.
Instead, hummingbirds use a forked tongue with a long groove on either half. When the hummingbird extends its tongue, its beak compresses the grooves and squeezes them together. Once the tongue reaches nectar, the grooves expand, which draws nectar up along the full length of the tongue grooves. This allows the bird to fill its tongue much faster than it could otherwise, enabling the hummingbird to lick up nectar more than 10 times a second.
There’s a neat excerpt from a documentary including this research over here (Tumblr won’t allow the embedded version); the full documentary premieres today on PBS. (Image credits: A. Rico-Guevara et al., sources 1,2; submitted by mypronounsareherrchancellor)