Hummingbird Tongues Are Little Nectar Pumps

How do hummingbirds guzzle nectar with their long bills? With miniature tongue pumps.

In a new study in the Proceedings of the Royal Society B, scientists filmed 18 hummingbird species drinking nectar. They discovered that when a hummingbird goes foraging for food, it sticks its long tongue out (twice the length of its bill) into flowers to reach the nectar inside. The hummingbird compresses its tongue flat as it pokes it down into the flower in search of nectar. Once it tastes the sugary concoction, it reshapes its tongue, drawing liquid up as the elastic grooves in the tongue expand from their compressed, flattened state. 

Previously, researchers had thought that hummingbirds drank through capillary action (the same process that allows paper towels to soak up liquid), but in this study, scientists observed only one hummingbird lick that drew nectar through that process out of 96 foraging activities observed. The pump-based drinking mechanism is much faster than drinking through capillary action—think of the difference in soaking up a cup of water with a paper towel versus drinking it out of a straw—allowing hummingbirds to feed much faster. 

This study means that scientists will have to rethink their estimations of hummingbirds’ energy intake, since the birds probably eat much more than previously estimated.