Featured Research

from universities, journals, and other organizations

Mystery of elephant infrasounds revealed

Date:
August 3, 2012
Source:
University of Vienna
Summary:
An international team of voice researchers and cognitive biologists provides new insights into the production of elephant communication. The so-called "infrasounds", i.e. sounds with pitches below the range of human hearing, are found to be produced with the same physical mechanism as human speech or singing.

African elephants in the Amboseli National Park, Kenia.
Credit: Copyright Department of Cognitive Biology, University of Vienna

In the current edition of Science, an international team of voice researchers and cognitive biologists led by Christian Herbst, Angela Stoeger and Tecumseh Fitch, provides new insights into the production of Elephant communication. The so-called "infrasounds," i.e. sounds with pitches below the range of human hearing, are found to be produced with the same physical mechanism as human speech or singing.

Related Articles


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.


Story Source:

The above story is based on materials provided by University of Vienna. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. T. Herbst, A. S. Stoeger, R. Frey, J. Lohscheller, I. R. Titze, M. Gumpenberger, W. T. Fitch. How Low Can You Go? Physical Production Mechanism of Elephant Infrasonic Vocalizations. Science, 2012; 337 (6094): 595 DOI: 10.1126/science.1219712

Cite This Page:

University of Vienna. "Mystery of elephant infrasounds revealed." ScienceDaily. ScienceDaily, 3 August 2012. <www.sciencedaily.com/releases/2012/08/120803103421.htm>.
University of Vienna. (2012, August 3). Mystery of elephant infrasounds revealed. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2012/08/120803103421.htm
University of Vienna. "Mystery of elephant infrasounds revealed." ScienceDaily. www.sciencedaily.com/releases/2012/08/120803103421.htm (accessed March 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lioness Has Rare Five-Cub Litter

Raw: Lioness Has Rare Five-Cub Litter

AP (Mar. 27, 2015) — A lioness in Pakistan has given birth to five cubs, twice the usual size of a litter. Queen gave birth to two other cubs just nine months ago. (March 27) Video provided by AP
Powered by NewsLook.com
Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) — Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Bear Cubs Tumble for the Media

Bear Cubs Tumble for the Media

Reuters - Light News Video Online (Mar. 26, 2015) — Two Andean bear cubs are unveiled at the U.S. National Zoo in Washington, D.C. Alicia Powell reports. Video provided by Reuters
Powered by NewsLook.com
Botswana Talks to End Illegal Wildlife Trade

Botswana Talks to End Illegal Wildlife Trade

AFP (Mar. 25, 2015) — Experts are gathering in Botswana to try to end the illegal wildlife trade that is decimating populations of elephants, rhinos and other threatened species. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


How Elephants Produce Their Deep 'voices': Same Physical Mechanism Produces Vocalizations in Elephants and Humans

Aug. 2, 2012 — Elephants rely on the same mechanism that produces speech in humans (and the vocalizations of many other mammals) to hit the extremely low notes they use to ... read more

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins