Perhaps you wonder, as I did, how hummingbirds are able to drink nectar if their beaks aren't long enough to reach it.
It's even more curious when hummers are able to drink nectar from a spout that's way above the current level of the nectar, as in the image below, where the water line seems to be at least an inch from the hummer's beak....
The Cottage Hummingbird Feeder (Aqua)
Does he suck up the water?
That's pretty much what biologists believed until 2011....
Well, Hummingbirds do have long tongues as well as long beaks. Especially when they are young, hummer tongues can even be longer than their beaks.
via PhysOrg.com (A juvenile male black-throated mango hummingbird (Anthracothorax nigricollis)
extending his tongue after drinking nectar. Credit: Kristiina Hurme, CC BY-ND
Secondly, a hummer actually has a split tongue (or two tongues) that are laterally perpendicular.
via PhysOrg.com Hummingbird tongue capture from slow motion
In 2011, University of Connecticut researcher Alejandro Rico-Guevara published his and his colleagues discovery shown through microscopic slow motion video: that when closed the two tongues press together to form a bond. When the hummingbird feels the nectar at the tip of the tongue, the tongues separate and the fluid enters the vacuum between them. Concurrently, the flexible spines on the tongue that you see in the above photo, move the nectar backward, bringing the tongue back into the beak as well. This movement occurs about 8 times per second!
Here is Dr. Rico-Guevara's own description:
"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." (via)
This will help you to visualize the movement. It is a microscopic look at a hummer's tongue recorded through a clear glass feeder. (There is no verbal narrative on the video, so feel free to turn down the music volume.)
Here is a schematic diagram of the licking cycle in hummingbirds based on the above video...
via PhysOrg.com
What is even more remarkable about Rico-Guevara's discovery is that it took until 2011 to learn exactly how the hummingbird obtained his nectar. Since 1833, it was believed that hummingbirds' used capillary action to suck fluids backward to the throat.
Researchers still don't know how hummingbirds swallow....
Sources: The Atlantic, PhysOrg.
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