Chameleons are a species that have long mystified humans. Unlike regular lizards, they have special features including parrot-like feet, eyes that can look at different directions at the same time and camouflaging ability that allows them to blend into the background.
And now the scientists discovered another neat little trick of chameleons: saliva that is 400 times stickier than human saliva.
An efficient hunter, people have long believed that chameleons change color to hunt preys before it was revealed that their color-changing camouflage is just meant to reflect their mood. So if color changing isn't really the chameleon's secret hunting weapon--what is? Well, it's at the tip of their tongue.
Although it has been known for years that chameleons have sticky tongues that they use when hunting, the study marks the first time the mechanical properties of the mucus is measured. According to Daily Nation, the viscosity, or thickness, of chameleon spit had never before been measured, except by the paper.
In other words, the paper has provided an answer as to how and why chameleons are able to hold on to prey while swiftly drawing it in its mouth at such high speed.
According to a paper published in the journal Nature Physics, the tongue of the chameleon has a mucus which has the same viscosity as honey. Once it sticks out its tongue to catch its prey, the tongue captures it viciously and retracts in highspeed, bringing it to its mouth.
By measuring the viscosity of the mucus on their tongue, they have found out that it is sticky enough to capture a prey up to a third of their body weight.
"The factor that limits the size of the prey is probably the size of the mouth of the chameleon," Pascal Damman, a physicist at the University of Mons in Belgium told the Christian Science Monitor..
Unlike other reptiles whose feeding strategy is to chase the prey, chameleons sit and wait. Once the prey is in sight, they use their deadly tongue, which is not only sticky, but can stretch twice their body length.
As to how the chameleons are able to loosen the tie once the prey is on their mouth, the researchers said they can only hypothesize that between the feeding stage, a non-sticky saliva is used so they can eat and swallow the prey.