Capillary action
The movement of a liquid through a narrow tube or space, sometimes against gravity. It results from the combined effects of cohesion, adhesion, and surface tension.
Hummingbirds do not draw nectar through capillary action — their tongue is a fluid trap. The forked tip opens when it touches nectar and snaps shut as the tongue retracts, scooping up liquid in the process. The finding overturned a century-old textbook explanation.
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