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 A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>