A male Allen’s Hummingbird, Santa Cruz.

image_3146e-Hummingbird-Tongue

A male Allen’s hummingbird (Selasphorus sasin) near Santa Cruz, CA. Image credit: Shravans14 / CC BY-SA 4.0.
Since the 1830s, ornithologists have assumed that hummingbirds drink by capillary action (wicking), the passive process of a fluid rising into a narrow tube because of forces attracting the liquid to the tube’s solid internal surface.
A new study, led by Dr Alejandro Rico-Guevara from the University of Connecticut, debunks the ‘wicking theory’ and shows that the hummingbird’s tongue actually works as an elastic micropump.
Using high-speed cameras, Dr Rico-Guevara and co-authors filmed the tongue-nectar interaction in 18 hummingbird species, from seven of the nine main hummingbird groups throughout the Americas.
The results were published online today in the journal Proceedings of the Royal Society B: Biological Sciences.
“A hummingbird’s tongue, which can be stuck out about the same length as its beak, is tipped with two long skinny tubes, or grooves,” Dr Rico-Guevara explained.
“Rather than wicking, the nectar is drawn into the tongue by the elastic expansion of the grooves after they are squeezed flat by the beak.”
The tongue structure is collapsed during the time it crosses the space between the bill tip and the nectar pool, but once the tip contacts the nectar surface, the supply of fluid allows the collapsed groove to gradually recover to a relaxed cylindrical shape as the nectar fills it.
via Hummingbird Tongues Work Like Elastic Micropumps, Study Shows | Biology | Sci-News.com.

Please Leave A Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.