Scientists have discovered that tiny hummingbirds use an incredible biological system to drink nectar through their long tongues.
In the past, researchers believed hummingbirds feasted on flower nectar through a process called "wicking," in which capillary actions allow liquid to flow through small openings, the University of Connecticut reported. New research has debunked that theory by demonstrating how the birds instead use "tiny pumps" to extract liquid from flowers.
A team of researchers looked at 18 hummingbird species using high-speed video cameras and observed that their tongues act as tiny pumps. The study offers the largest data set on hummingbird feeding mechanics to date.
The findings revealed hummingbird tongues are equipped with two small tubes or "grooves" that use elastic expansion to draw nectar in after they are squeezed flat by the beak. When the tongue is pushed out past the beak tip, the structure is collapsed, but once the grooves enter the nectar pool, the fluid relaxes them into cylindrical shapes that can then be filled. When the hummingbird squeezes the nectar off its tongue by protruding it, the grooves collapse and move elastic energy into the groove walls. The energy created through this process creates a pumping action that allows the bird to harvest nectar; this entire process takes place in less than a tenth of a second.
The findings could provide insight into the relationship between hummingbirds and flowers, and also have implications into hummingbird evolution because their ability to drink nectar is believed to have made them what they are today.
"Our research shows how they really drink and provides the first mathematical tools to accurately model their energy intake," said research scientist Alejandro Rico-Guevara, "which will in turn inform our understanding of their foraging decisions and ecology."
The findings were published in a recent edition of the journal Proceedings of the Royal Society B: Biological Sciences.
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