An amazing new finding by scientists could totally alter how we understand frogs and the way they prey on insects and animals.
Scientists studying frogs have just discovered something absolutely amazing: the sticky tongue uses a non-Newtonian liquid to capture prey in a fraction of a second, something not seen anywhere else in the animal kingdom. Researchers looked into what kind of special saliva frogs have that enable them to grab prey, sometimes in mid-air, and found that it is a very unique liquid indeed.
The saliva has the consistency of snot and attaches to the prey, letting the frog yank it back into his mouth at a force 12 times the strength of gravity. The frog is able to nab prey 1.4 times their body weight, which is more than anything humans have ever created.
A non-Newtonian fluid is something that acts like both a liquid and a solid. If you mixed corn starch and water, for example, it would flow like liquid but act like a solid when you press it. The frog’s saliva is the opposite: it acts like a liquid when it attaches to the prey, but turns solid as it fills the cracks of the prey.
The abstract states: “Frogs can capture insects, mice and even birds using only their tongue, with a speed and versatility unmatched in the world of synthetic materials. How can the frog tongue be so sticky? In this combined experimental and theoretical study, we perform a series of high-speed films, material tests on the tongue, and rheological tests of the frog saliva. We show that the tongue’s unique stickiness results from a combination of a soft, viscoelastic tongue coupled with non-Newtonian saliva. The tongue acts like a car’s shock absorber during insect capture, absorbing energy and so preventing separation from the insect. The shear-thinning saliva spreads over the insect during impact, grips it firmly during tongue retraction, and slides off during swallowing. This combination of properties gives the tongue 50 times greater work of adhesion than known synthetic polymer materials such as the sticky-hand toy. These principles may inspire the design of reversible adhesives for high-speed application.”