Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oral flex - Chameleon tongues have special muscle to haul in dinner

12.10.2001


Unique muscles let chameleons fire at food.
© SPL


Chameleons can reel in prey anywhere within two-and-a-half body lengths of their jaws. Their tongues can overcome even a bird’s weight and reluctance to be eaten. How? Muscles that are unique among backboned animals, researchers now reveal.

Anthony Herrel of the University of Antwerp, Belgium, and colleagues put crickets at different distances from the noses of two chameleon species, Chameleo calyptratus and Chameleo oustaletti. The tongues of these 12-cm-long reptiles pull at maximum strength on prey from 5-30 centimetres away, the team found.

Such versatility is beyond normal muscle: "it wouldn’t be able to pull back," says Herrel. Muscle usually reaches its limit when its tiny pistons - filaments that slide back and forth over one another - are fully closed.



In the chameleons, the researchers discovered holes at the ends of each microscopic piston that allow the filaments to slide right through and carry on contracting. Insects have such ’supercontractile’ muscle, but this is a first in vertebrates.

The lizards’ muscle filaments also overlap more than usual when the tongue is fully extended (at six times its resting length). This increases the force that the muscle can exert. Finally, chameleon fire out, rather than poke out, their tongues. "Once it’s gone from the mouth it has its own trajectory - there’s very little control," says Herrel.

"These observations go a long ways towards explaining how chameleons can retract their tongues," agrees zoologist David Wake of the University of California, Berkeley. Wake has studied salamanders with a similar tongue-firing ability; he suspects that they might also have supercontractile muscle.

Too close for comfort

Chameleon tongues are less efficient with prey that is less than one-third of a body length away. A chameleon often retreats before firing out its tongue, to generate enough force to yank a meal from its perch.

Such specialization has evolved to capture large prey, Herrel believes. Chameleons sit and wait for food, so meals can be few and far between. "Any prey they see they need to be able to catch. If you only catch one prey item every few days, you want it to be as big as possible," he says.

References
  1. Herrel, A., Meyers, J. J., Aerts, P. & Nishikawa, K. C. Functional implications of supercontracting muscle in the chameleon tongue retractors. Journal of Experimental Biology, 204, 3621 - 3627 , (2001)

JOHN WHITFIELD | Nature News Service
Further information:
http://www.nature.com/nsu/011018/011018-2.html
http://www.nature.com/nsu/

More articles from Life Sciences:

nachricht Bolstering fat cells offers potential new leukemia treatment
17.10.2017 | McMaster University

nachricht Ocean atmosphere rife with microbes
17.10.2017 | King Abdullah University of Science & Technology (KAUST)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Ocean atmosphere rife with microbes

17.10.2017 | Life Sciences

Neutrons observe vitamin B6-dependent enzyme activity useful for drug development

17.10.2017 | Life Sciences

NASA finds newly formed tropical storm lan over open waters

17.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>