It’s a well-established fact that frog’s saliva is one of the stickiest material know to science. Regrettably, little to no research has been performed to study the properties of this fluid. However, a team of researchers from Georgia Institute of Technology working with the sometimes disgusting amphibians has managed to determine what makes the frog’s saliva so sticky.
Alexis Noel is a Ph.D. student at the Georgia Institute of Technology and the author of the new study involving frog saliva. The researcher declared that although some of the work they did on the frog specimens, like spending hours at an end scraping saliva from the frogs’ tongues, might be labeled as nauseating, he and his team managed to discover surprising facts about this amphibian’s hunting tool.
For example, during their experiments, which involved high-speed photography and saliva testing, the researchers have discovered that the frog’s saliva is actually a non-Newtonian fluid.
As you know, normal fluids have a constant viscosity, which may change depending on pressure and temperature. Normal fluids tend to maintain their shape when they are poured into a container. Now, non-Newtonian fluids, as their names suggest, don’t follow the usual rules, meaning that they don’t have a constant viscosity, and they can change shape under strain or stress.
A good example of a non-Newtonian fluid is honey. As long as it’s in a jar, the honey remains in its solid form. But if you apply some form of stress, like stirring, the honey will turn liquid.
Basically, this is what gives the frogs’ saliva that stickiness. Using high-speed photography, Noel and his colleagues analyzed the hunting behavior of over a dozen frogs. The results are fascinating, to say the least.
As Noel explained, the frog’s saliva is very dense, almost solid-like. However, upon leaving the frog’s mouth, the saliva changes its state from solid to liquid. Thus, as soon as the frog’s tongue touches the insect’s body, the saliva fills every crevice in the insect’s body. As soon the frog retracts its tongue, the saliva’s state changes again to allow the frog to reel in its prey.
Noel’s findings were published in the Journal of the Royal Society. As for the ramifications of Noel’s study, the scientist believes that the frog’s saliva might provide us with vital clues to creating improved adhesives.
In the end, it would seem that scraping saliva from a frog’s tongue was a necessary evil, and the first step in the right direction.
Image source: FreeGreatPicture