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 The big clean up after stress
25.05.2018 | Julius-Maximilians-Universität Würzburg

nachricht Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>