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  Newsmakers   Chameleon’s secret of sticky mucus revealed

Chameleon’s secret of sticky mucus revealed

AFP
Published : Jun 21, 2016, 2:33 am IST
Updated : Jun 21, 2016, 2:33 am IST

A stunningly efficient hunter, the chameleon relies on an impressive biological arsenal that includes colour-changing camouflage, panoramic vision, and lots of patience.

A stunningly efficient hunter, the chameleon relies on an impressive biological arsenal that includes colour-changing camouflage, panoramic vision, and lots of patience. And then there’s that lightning-fast tongue.

The reptile’s tongue-lashing prowess has been extensively researched over the years, but one ability has remained a mystery: How does the chameleon’s fleshy projectile hold on to prey while snapping it back towards its mouth at such high speed Several mechanisms have been proposed: suction, stickiness, or a velcro-like bond between a rough surface on the chameleon’s tongue and that of its meal, which can weigh a third as much as the predator itself.

On Monday, scientists in Belgium and France said the answer was sticky mucus on the tongue tip.

“We were surprised to find that the liquid is very viscous, about 1,000 times more so than (human) saliva,” said Pascal Damman of the University of Mons in Belgium, who co-authored a study published in the journal Nature Physics. The viscosity, or thickness, of chameleon spit had never before been measured, he told AFP. The team then used mathematics to calculate the adhesive properties, or stickiness, that such viscosity would convey.

“Contrary to what many thought, the viscous adhesion is more than sufficient to allow the chameleon to haul in such big prey,” said Damman. Sometimes, he added, “the simplest explanation (is) the best one.”

The chameleon is known as a “sit-and-wait” predator — unlike other reptiles that scramble after their lunch, it stays hidden, motionless, until its prey comes within striking distance.

Location: France, Île-de-France, Paris