May 8, 2011 | David F. Coppedge

Hummingbird Tongue More Clever Than Thought

Humans sip their nectar by tipping a glass and slurping, but how can a hummingbird pull liquid out of flowers with a tongue alone?  Up until now, scientists thought that hummingbird tongues acted like capillary tubes.  New research with high-speed cameras show that the action is much more clever – so clever it might lead to advances in human machinery.
    PhysOrg posted a summary of a paper on PNAS,1 where scientists from the University of Connecticut decided to check out how hummingbirds do it.  Using high-speed cameras on 30 hummingbirds from 10 species, Rico-Guevara and Rubega discovered that the hummingbird tongue acts as a fluid trap, not a capillary tube. 
    The tongue splits into two parts, lined with hair-like extensions called lamellae.  As the bird pulls the tongue out from the nectar, the two parts come together automatically and trap the nectar, pulling the food into the mouth.  The PhysOrg article includes four video clips showing the action in slow motion.
    The researchers further discovered that the same action occurs when the tongue of dead birds is pulled through simulated nectar, showing it is an automatic action, “therefore highly efficient because no energy expenditure by the bird is required to drive the opening and closing of the trap.”  According to the article, hummingbirds flick their tongues in and out of the nectar as fast as 20 times per second.
    The abstract from the paper ended with a tantalizing hint of where this research can lead: “We propose a conceptual mechanical explanation for this unique fluid-trapping capacity, with far-reaching practical applications (e.g., biomimetics).”
    Bird lovers will want to watch the entertaining performance on Science Nation of Griffin, an African gray parrot, posted on Live Science.  Is this bird really smart enough to understand shapes and colors, or is it responding to subconscious cues from its trainers?  Whether or not you believe Irene Pepperberg’s claim that they controlled for such cues, everyone will agree that “bird brains” are “smarter than you think.”
    David Catchpoole at wrote about the brilliant colors of parrots and commented in a sidebar about Dr. Pepperberg’s work on parrot intelligence.  Meanwhile, PhysOrg wrote about how physicists at Yale University have found a way to improve lasers by imitating the techniques birds use to flash bright colors.

1.  Rico-Guevara and Rubega, “The hummingbird tongue is a fluid trap, not a capillary tube,” Proceedings of the National Academy of Sciences, published online before print May 2, 2011, doi: 10.1073/pnas.1016944108.

Hummingbirds and parrots are not only beautiful, they are well designed and intelligent.  We hope this Amazing Facts entry will grant you even more appreciation as you watch the hummingbird feeder.  If you don’t have one, go get one; the performances will delight and astonish the family.  For a good film sequence about the design of hummingbirds, get the beautiful film God of Wonders at RPI, where you can buy copies in bulk to share with friends and acquaintances.

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