A new study published on February 1st, 2017 by The Royal Society has shone some light on the science behind frogs’ very distinctive ability to catch prey. The paper, co-authored by scientists from the Georgia Institute of Technology and the Atlanta Botanical Garden, made some very interesting discoveries surrounding the adhesive nature of a frogs’ tongue.
It had been previously assumed that the saliva coating the creature’s tongue acted upon prey in a pressure-sensitive manner, not dissimilar to the properties of the adhesive tapes we ourselves use. However, the study proved that the stickiness that makes up a frog’s tongue is due to the physical properties of the tongue mixed with the non-Newtonian properties of its saliva. In simpler terms, the energy surrounding the adhesion are more related to viscosity and velocity than contact stickiness. The scientists described the interaction as follows:
“Paint is thrown onto a wall with a brush, flowing at high speeds to create an even coating. At low speeds, it clings to the wall. In the same way, the saliva coats the insect on impact, but sticks to the prey in retraction. Our study shows that an even and thin coating of the saliva is critical to prey capture. This study points to the importance of the saliva in prey adhesion. In addition, the densely packed papillae create a composite-like surface structure which may aid in continuous adhesion of saliva to tissue, much like a hydrogel.”
In addition to their findings on the adhesive properties, the researchers concluded that frogs’ tongues consist of “one of the softest biological materials known” and that it acts as a shock absorber, wrapping around prey, gripping it and coating it in the saliva before bringing it back to its’ mouth. The entire process, which take mere seconds, is in its own right a biological marvel.
The team of scientists theorized that such traits could “be useful in designing reversible adhesives that stick at high speed”, and could be something that might help revolutionize how we think and use adhesive tools. Admittedly a very niche market, industries within it could very well be interested in the findings of this study, but there is no word as to if it has drawn any attention outside of the scientific community.