Slip of the tongue: Chameleon's sticky secret revealed

2016-06-20 21:34


Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories


Black mamba vs chameleon

2014-06-26 10:23

Check out this rather uneven battle between the species filmed in the Kruger National Park. WATCH

Paris - 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."

Tip of its tongue

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.

It changes colour to become one with the background. Independently-rotating eyes with a near-360°-field of vision means the animal doesn't have to move its head while lying in ambush.

When a meal makes its appearance, the lizard takes aim and shoots - extending its deadly tongue up to double its body length.

But a question remains: How does the creature loosen the catch from its sticky tongue for swallowing?

"We can only hypothesise," said Damman.

It may use a "normal", non-sticky saliva from elsewhere in the mouth to break the bond.

Or it may simply wait for the adhesion to wear off naturally.

In viscous adhesion, the stronger and faster the pull of the tongue on the insect, the stronger the bond will be, explained the researcher.

As the tongue relaxes, the adhesion will similarly loosen and ultimately disappear, allowing the chameleon to chow down - without biting its tongue.

Read more on:    belgium  |  research  |  reptiles

Join the conversation! encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

Inside News24


Book flights

Compare, Book, Fly

Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.