Chameleon catching prey
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Chameleon spit is 400 times thicker than human's

Chameleons are well known for their lengthy tongues and speedy eating, as shown in this video, but another critical tool helps them trap their prey: spit. The lizards sport saliva that is about 400 times more viscous than that of humans, researchers report online today in Nature Physics. Scientists collected the saliva from five chameleons by placing a microscope slide between each lizard and its prey. They then placed the mucous-laden slides onto an incline and rolled a steel ball down them. High-speed cameras recorded the velocity of each ball, allowing the team to calculate how much the saliva slowed the ball down. Chameleon saliva was found to have an average viscosity of 0.4 pascal-seconds (Pa·s)—about 400 times thicker than human saliva. This sticky spit helps the lizards capture prey weighing up to 30% of each reptile’s body weight with solely their tongues. The researchers are looking to test the tongues of other reptiles and amphibians to see how much sticky spit is used in the animal kingdom.