Navigation Links
Mystery of elephant infrasounds revealed

Elephants can communicate using very low frequency sounds, with pitches below the range of human hearing. These low-frequency sounds, termed "infrasounds", can travel several kilometers, and provide elephants with a "private" communication channel that plays an important role in elephants' complex social life. Their frequencies are as low as the lowest notes of a pipe organ.

Although the sounds themselves have been studied for many years, it has remained unclear exactly how elephant infrasounds are made. One possibility, favored by some scientists, is that the elephants tense and relax the muscles in their larynx (or "voice box") for each pulse of sound. This mechanism, similar to cats purring, can produce sounds as low in pitch as desired, but the sounds produced are generally not very powerful.

The other possibility is that elephant infrasounds are produced like human speech or singing, but because the elephant larynx is so large, they are extremely low in frequency. Human humming is produced by vibrations of the vocal folds (also called "vocal cords"), which are set into vibration by a stream of air from the lungs, and don't require periodic muscle activity. By this hypothesis, elephant infrasounds result simply from very long vocal folds slapping together at a low rate, and don't require any periodic tensing of the laryngeal muscles.

To find out, researchers at the University of Vienna, led by voice scientist Christian Herbst and elephant communication expert Angela Stoeger, removed the larynx from an elephant (which died of natural causes), and brought it into the larynx laboratory of the Department of Cognitive Biology (headed by Tecumseh Fitch). By blowing a controlled stream of warm, humid air through the larynx (substituting for the elephants lungs), and manually placing the vocal folds into the "vocal" position, the scientists coaxed the vocal folds into periodic, low-frequency vibrations that match infrasounds in all details.

Since there can be no periodic tensing and relaxing of vocal fold muscles without a connection to the elephant's brain, low-frequency vibrations in the excised larynx clearly demonstrate that the "purring" mechanism is unnecessary to explain infrasounds. Thus, elephants "sing" using the same physical principles as we do, but their immense larynx produces very low notes.

As an additional insight, the scientists were able to get a very clear look at some fascinating types of vibration called "nonlinear phenomena". When a baby cries, or a heavy metal singer screams, the vocal folds vibrate in an irregular manner, which is very grating to our ears. Young elephants also scream and roar, and the mechanism they use is again identical to that seen in humans.

This research shows that the physical principles underlying the human voice extend over a remarkable range, from bat's incredibly high vocalizations (too high for us to hear), all the way down to elephants' subaudible infrasounds. How whales, the largest animals, make their even lower frequency sounds remains to be determined.


Contact: Dr. Christian Herbst
University of Vienna

Related biology news :

1. Animal reservoir mystery solved
2. New discovery provides insight on long-standing pregnancy mystery
3. Mystery to the origin of long-lived, skin-deep immune cells uncovered
4. UCLA life scientists unlock mystery of how handedness arises
5. Kidney stone mystery solved
6. Study shows how elephants produce their deep voices
7. Elephant seal tracking reveals hidden lives of deep-diving animals
8. The absence of elephants and rhinoceroses reduces biodiversity in tropical forests
9. Detector of DNA damage: Structure of a repair factor revealed
10. Key part of plants rapid response system revealed
11. Ancient giant turtle fossil revealed
Post Your Comments:
Related Image:
Mystery of elephant infrasounds revealed
(Date:11/17/2015)... , November 17, 2015 ... au 19 novembre  2015.  --> Paris ... --> DERMALOG, le leader de l,innovation biométrique, ... la fois passeports et empreintes sur la même surface ... les passeports et l,autre pour les empreintes digitales. Désormais, ...
(Date:11/12/2015)... CAMBRIDGE, Mass. , Nov. 12, 2015 /PRNewswire/ ... Broad Institute of MIT and Harvard for use ... chemical discovery information management tools. The partnership will ... share both biological and chemical research information internally ... tools will be used for managing the Institute,s ...
(Date:11/9/2015)... , Nov. 09, 2015 ... addition of the "Global Law Enforcement ... offering. --> ) has ... Law Enforcement Biometrics Market 2015-2019" report ... and Markets ( ) has announced ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... Md. , Nov. 30, 2015 ... development company committed to the fostering and monetization ... the current and prospective initiatives designed to create ... Chief Executive Officer of Spherix. "Based on published ... future licensees exceeds $50 billion and Spherix will ...
(Date:11/30/2015)... , Nov. 30, 2015  Champions Oncology, Inc. (CSBR), ... services to personalize the development and use of oncology ... Executive Officer, will be presenting at the LD MICRO ... Pacific Standard Time (PST).  The conference, held at the ... Angeles, CA , will feature 200 small/micro-cap companies ...
(Date:11/30/2015)... 30, 2015 TapImmune, Inc. ... of innovative peptide and gene-based immunotherapeutics and vaccines for ... it will be presenting at the 8 th ... at 2.30 PM PT. Dr. John N. Bonfiglio ... be giving the presentation and will join TapImmune management ...
(Date:11/30/2015)... , Nov. 30, 2015  Aytu BioScience, Inc. (OTCQB: ... and related conditions, will present at two upcoming investor ... an interactive real-time virtual conference, to be held December ... Conference, to be held December 2 nd & ... and streamed live via webcast. ...
Breaking Biology Technology: