Sticky frog tongue could lead to adhesive innovation

KIEL, Germany, June 12 (UPI) -- Trying to figure out how to measure the stickiness of a frog's tongue isn't an everyday problem, but it was the central problem for researchers at Kiel University in Germany, who wanted to better understand how the Amazon horned frog hunts and captures its prey.

The horned frog of the Amazon doesn't just slurp up lazy, unsuspecting insects. They hunt and eat lizards, snakes, rodents, other frogs and even small birds. Who knew something that hops around and croaks could be so vicious?

The horned frog's especially adhesive tongue is what allows it to capture and consume such large prey.

The German researchers measured the frog's tongue in action by placing crickets on the other side of a piece of glass and tempting the frog to lunge for the insects. Researchers measured the force of the frog's tongue on the glass.

"What we actually found was that the tongue adhesive forces were well beyond the body weight of these frogs," explained lead researcher Thomas Kleinteich, author of the study published this week in the journal Scientific Reports.

The frog can lift some 1.4 times its body weight using its tongue. To put it human terms: it's the equivalent of a 176-pound person lifting 246 pounds using only his or her tongue.

The adhesive catch and release happens in a matter milliseconds.

"And, another thing which we found, which I did not expect, was that the mucus or the slime on top of their tongues does not seem to be that important as people always assumed," Kleinteich added.

Kleinteich and his fellow researchers think further analysis of the frog's unique and impressive wet-adhesive system could inspire product engineers who need to develop adhesive technologies that work in damp settings.