A new study has revealed that hummingbirds actually use their tongue like a "pump," instead of employing capillary action.
Scientists and birdwatchers were equally shocked this week to learn that a commonly held convention about hummingbirds’ tongues was totally off base. According to a report from Live Science, instead of using capillary action, a process by which fluids travel through extremely narrow spaces, hummingbirds actually use their tongues as elastic micropumps, allowing them to consume nectar at a much faster rate.
Researchers believed hummingbirds used capillary action for so long because of the long groves on their tongues that look like open cylinders. Using high-speed cameras to watch hummingbirds feed, however, researchers at the University of Connecticut realized that this was not actually occurring at all.
The way hummingbirds collect nectar is actually more similar to drinking through a straw. The bird flattens its tongue until it comes into contact with nectar, at which point it opens up and creates a vacuum. This draws the nectar in through the tube and into the hummingbird’s mouth, just like a drinking straw would.
The elastic nature of the hummingbird’s tongue allows it to store energy that is transferred to the act of moving nectar out of a flower. Using this technique, hummingbirds can drain up to 10 drops of nectar from a flower in about 100th of a second.
Scientists filmed 96 different feeding sessions from 32 birds across 18 different species, and spent hours examining the footage to determine what was going on as they fed. Capillary action would not allow the birds to consume nectar at the rate observed, and the new insights explain how hummingbirds make the most out of their feeding sessions.