A new study published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences, unveils the secret behind how hummingbird tongues work.
According to The Washington Post, it was previously believed by scientists that hummingbirds used capillary action to sip nectar in tiny bursts. Capillary action is a force that acts like a straw in a glass of water, but without the application of suction. Until now, scientists thought the long, narrow grooves observed on the tongues of hummingbirds enabled capillary action.
Study authors Alejandro Rico-Guevara and Kristiina Hurme of the University of Connecticut uncovered how the birds’ tongues actually work in their research: the tongues work like tiny mechanical pumps.
When a hummingbird feeds, its tongue flicks in and out of its beak fifteen to twenty times per second, Discovery Magazine explains. After each lick, the hummingbird draws its tongue back inside their bill, which squeezes the nectar out of the tongue from the two tubes at the end.
The entire tongue transforms shape during feeding and “that transformation of the tongue shape is what actually pulls the fluid inside,” said Rico-Guevara.
What we found is that there is actually a micropump which is transforming the whole tongue shape, and that transformation of the tongue shape is what actually pulls the fluid inside.
In an article for The Conversation, Rico-Guevara and Hurme explain that birds are incapable of using their tongues as straws, so instead of generating suction, “the system works like a tiny pump, powered by the springiness of the tongue.”
The grooves in the hummingbird tongue don’t reach the throat, so the bird cannot use them as tiny straws. For this reason, instead of using vacuum to generate suction – imagine drinking lemonade out of a straw – the system works like a tiny pump, powered by the springiness of the tongue. The bird squashes the tongue flat, and when it springs open, this expansion rapidly pulls the nectar into the grooves in its tongue. It turns out it’s elastic energy – potential mechanical energy stored by the flattening of the tongue – that lets hummingbirds collect nectar much faster than if they relied on capillarity.
Scientists recently discovered the fossils of an ancient bird – about the size of a hummingbird – in Brazil which is helping researchers discover more about the evolution of birds.
