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 Turning carbon dioxide into liquid fuel
06.08.2020 | DOE/Argonne National Laboratory

nachricht Tellurium makes the difference
06.08.2020 | Friedrich-Schiller-Universität Jena

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>