For over 180 years, we have misunderstood the working procedure of hummingbird tongues; at least a new study published in the journal Proceedings of the Royal Society B: Biological Sciences is suggesting so.
Since the early 19th century, scientists have believed that tongue of hummingbirds use capillary action for slurping up nectar from flowers. For those who don’t know: the term capillary action is used for an act during which liquid flows through constricted areas, even going against gravitational force.
According to Alejandro Rico-Guevara, the scientist leading this new study, researchers came to this conclusion as tongues of these birds carry long groves which have significant resemblance with open cylinders. Rico-Guevara represents the University of Connecticut as a functional morphology research associate.
However, capillary action is pretty slow, especially by the standards set by hummingbirds. Researchers conducting this new study used high-speed videos to discover that the tongues of these birds actually act as elastic micro-pumps. This action of their tongues allows the hummingbirds to feed at extremely high speeds.
The majority of us are familiar with conventional pumps, for instance, the straws we use for drinking beverages. When we sip a drink using a straw, we need to contort our cheeks. According to Rico-Guevara, this action of our cheeks allows us to create a vacuum within the straw and suck the liquid up.
The researchers are saying that the working procedure of hummingbird’s tongue is slightly similar to that of a drinking straw; the most significant difference between the two procedures is that hummingbird’s tongue work without using any vacuum. These birds flatten their outstretched tongue, and it remains flattened until it comes in contact with the nectar. The researchers further wrote that after coming in contact with the nectar surface, the shape of the tongues change as a result of being filled with nectar.
For pulling the nectar in, the birds bend the top of their tongue, which means the tongue no longer remains flat. According to Rico-Guevara, this bending results in storage of elastic energy. This energy assists the birds in drawing the nectar out from the flower into their mouth.
This is a pretty fast technique and according to the researchers, it allows hummingbirds to drain 5 to 10 drops of floral nectar within just 15 milliseconds.