Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Snakes can Hear Stereo Sound from the Sand

30.01.2008
Biophysicists of the Technical Universtiy Munich and Bernstein Center for Computational Neuroscience publish in Physical Review Letters
It is often believed that snakes cannot hear. This presumption is fed by the fact that snakes lack an outer ear and that scientific evidence of snakes

Copyright 2002: R.D.L. Mastenbroek & Dexter Bressers

responding to sound is scarce. Snakes do, however, possess an inner ear with a functional cochlea.

In a recent article in Physical Review Letters* scientists from the Technical University Munich (TUM), Germany, and the Bernstein Center for Computational Neuroscience (BCCN) present evidence that snakes use this structure to detect minute vibrations of the sand surface that are caused by prey moving. Their ears are sensitive enough to not only "hear" the prey approaching, but also to allow the brain, i.e., the auditory system, to localize the direction it is coming from. The work was carried out by J. Leo van Hemmen and Paul Friedel, scientists at the Biophysics Department of the TUM and BCCN, together with their colleague Bruce Young from the Biology Department of Washburn University at Topeka (KS, USA).

... more about:
»Sound »Surface »Vibration »Wave

Any disturbance at a sandy surface leads to vibration waves that radiate away from the source along the surface. These waves behave just like ripples on the surface of a pond after a stone is dropped into the water. The sand waves, however, propagate much quicker (the speed is about 50 meters per second) than at the water surface but on the other hand much more slowly than for instance in stone (or concrete) and the amplitude of the waves may be as small as a couple of thousands of a millimeter. Yet a snake can detect these small ripples. If it rests its head on the ground, the two sides of the lower jaw are brought into vibration by the incoming wave. These vibrations are then transmitted directly into the inner ear by means of a chain of bones attached to the lower jaw. This process is comparable to the transmission of auditory signals by the ossicles in the human middle ear. The snake thus literally hears surface vibrations.

Mammals and birds can localize a sound source by comparing the arrival times of sounds that arrive at the right and left ear through air. For sound coming from the right, the right ear will respond a fraction of a second earlier than the left ear. For sound coming from the left, the situation is exactly the other way around. From this time-of-arrival difference, the brain computes the direction that the sound comes from.

Combining approaches from biomechanics and naval engineering with the modeling of neuronal circuits, Friedel and his colleagues have shown that the snake can use its ears to perform the same trick for sound arriving through sand. The left and right side of the lower jaw of a snake are not rigidly coupled. Rather, they are connected by flexible ligaments that enable the snake to stretch its mouth enormously to swallow large prey. Both sides of the jaw can thus move independently, just like two boats floating - so to speak - on a sea of sand, and in this way allow for stereo hearing.

A sand wave originating from the right will stimulate the right side of the lower jaw slightly earlier than the left side, and vice versa. Using a mathematical model, the scientists calculated the vibration response of the jaw to an incoming surface wave. They could show that the small difference in the arrival time of the wave at the right and the left ear is sufficient for the snake's brain to calculate the direction of the sound source.

The extraordinary flexibility of the lower jaw of snakes has evolved because being able to swallow very large meals is a big advantage if food is in short supply and competition fierce. Moreover, the separation of the sides of the lower jaw also allowed this very interesting form of hearing to develop.

Paul Friedel, Bruce A. Young, and J. Leo van Hemmen
Auditory localization of ground-borne vibrations in snakes
Physical Review Letters 100, 048701 (2008)
doi: 10.1103/PhysRevLett.100.048701
For more information, please contact one of the authors.
Paul Friedel
Physik Department T35, TU München
Garching bei München, Germany
pfriedel@ph.tum.de
+49 89 289 12193
Prof. J. Leo van Hemmen
Physik Department T35, TU München
Garching bei München, Germany
lvh@tum.de
+49 89 289 12362
Prof. Bruce A. Young
Department of Biology
Washburn University
Topeka, KS 66621, USA
bruce.young@washburn.edu
+1 785 670 2166

Katrin Weigmann | idw
Further information:
http://www.t35.ph.tum.de/
http://www.bernstein-zentren.de/

Further reports about: Sound Surface Vibration Wave

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>