Scientists found out that the stickiness of frog's tongue is influenced by its saliva. Using a multi-pronged approach, dozens of frogs and their feeding mechanisms were analyzed. The researchers also conducted collection of saliva samples from 17 scraped tongues of the amphibian for microscopic analysis.
Researchers said that the texture of the amphibian's tongue is comparable to a chewed gum. With that, a bond that does not break easily will be created when a finger is placed on the amphibian's tongue.
Similarly, the lingual appendage stretches and wraps around a prey coming contact to the organ. Head researcher Alexis Noel described "if you imagine the tongue was very stiff like the human tongue, you wouldn't have much coverage."
She added that the amphibian's organ of taste is 10 times softer than human's which makes it "one of the softest bio tissues known" and is almost similar to the consistency of brain tissues.
Noel explained that the stickiness is due to the organ's sturture and saliva. Frogs spit on their prey with a watery material for easier and tighter grip. The consistency of their saliva on the back of their mouth is stickier and thicker than honey. The mechanical engineer from the Georgia Tech, Atlanta also likened the saliva to a "reversible adhesive."
According to the study published in the Journal of the Royal Society Interface the travel speed of the saliva on the amphibian's mouth affects its thickness. It was discovered that in order to have watery from sticky spit, frogs have to "push their eyeballs back into their heads and into their tongue." This movement relaxes the salivary grip allowing the insect slide down into the predator's mouth.
Further, frogs do not have salivary glands in their mouths unlike other organisms. However, their tongue directly secretes the digestive material. Other than frogs, chameleons also have sticky tongues. According to the study of Pascal Damman, the latter uses its stretchable organ and mucoid saliva to catch its meal.