Featured Research

from universities, journals, and other organizations

How elephants produce their deep 'voices': Same physical mechanism produces vocalizations in elephants and humans

Date:
August 2, 2012
Source:
American Association for the Advancement of Science
Summary:
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 communicate.

African elephants are known to be great communicators that converse with extremely low-pitched vocalizations, known as infrasounds, over a distance of miles.
Credit: catfish07 / Fotolia

African elephants are known to be great communicators that converse with extremely low-pitched vocalizations, known as infrasounds, over a distance of miles. These infrasounds occupy a very low frequency range -- fewer than 20 Hertz, or cycles, per second -- that is generally below the threshold of human hearing.

Related Articles


Now, a new study shows that elephants rely on the same mechanism that produces speech in humans (and the vocalizations of many other mammals) to hit those extremely low notes. Christian Herbst from the University of Vienna, along with colleagues from Germany, Austria and the United States, used the larynx of a recently deceased elephant to recreate some elephant infrasounds in a laboratory.

Their findings are published in the 3 August issue of the journal Science, which is published by AAAS, the nonprofit science society.

"These vocalizations are called infrasounds because their fundamental frequency is below the range of human hearing," explained Herbst during a phone interview. "We only hear the harmonics of such sounds, or multiples of that fundamental frequency. If an elephant's vocal folds were to clap together at 10 Hertz, for example, we would perceive some energy in that sound at 20, 30, 40 Hertz and so on. But these higher overtones are usually weaker in amplitude."

Until now, researchers have wondered whether these low, rumbling elephant infrasounds were created by intermittent muscle contractions, as a cat's purr is, or by flow-induced vocal fold vibrations, fueled by air from the lungs, as is a human's voice. But, the natural death of an elephant at a zoo in Berlin gave Herbst and his colleagues a somewhat serendipitous chance to study the mechanism firsthand.

The researchers removed the elephant's larynx and froze it within a few hours of the animal's death. They then took it over to the larynx laboratory in the Department of Cognitive Biology at the University of Vienna, where Tecumseh Fitch, a senior author of the Science paper, studied it in depth.

Herbst and the other researchers imitated the elephant's lungs by blowing controlled streams of warm, humid air through the excised larynx while adjusting the elephant vocal folds into a phonatory, or vocal-ready, position. In this way, the scientists were able to coax the vocal folds into a periodic, low-frequency vibration that matched an elephant's infrasound in every detail.

The fact that they were able to duplicate the elephant's infrasounds in a laboratory demonstrates that the animals rely on a myoelastic-aerodynamic, or "flow-driven," mode of speech to communicate in the wild. The elephant's brain would have been required to recurrently tense and relax the vocal muscles if the other mechanism, which produces a cat's purr, was involved, they say.

This flow-induced mechanism demonstrated by the researchers is likely to be employed by a wide range of mammals. From echolocating bats with their incredibly high vocalizations to African elephants and their extremely low-pitched infrasounds, this mode of voice production seems to span four to five orders of magnitude across a wide range of body sizes and sonic frequencies.

The researchers also saw some interesting "nonlinear phenomena" in the way the elephant vocal folds vibrated. These mostly irregular patterns of vibration occur when babies cry or heavy metal singers scream and the physical mechanism that elephants use is again identical to that seen in humans, they say.

"If I scream, it's no longer a periodic vibration," said Herbst. "It becomes chaotic and you can hear a certain degree of roughness. This can also be observed in young elephants, in situations of high excitement."

Herbst says that the findings were only made possible by a collaborative effort between voice scientists and biologists, and that voice science is an essential aspect of our social and economic lives.


Story Source:

The above story is based on materials provided by American Association for the Advancement of Science. 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:

American Association for the Advancement of Science. "How elephants produce their deep 'voices': Same physical mechanism produces vocalizations in elephants and humans." ScienceDaily. ScienceDaily, 2 August 2012. <www.sciencedaily.com/releases/2012/08/120802141527.htm>.
American Association for the Advancement of Science. (2012, August 2). How elephants produce their deep 'voices': Same physical mechanism produces vocalizations in elephants and humans. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2012/08/120802141527.htm
American Association for the Advancement of Science. "How elephants produce their deep 'voices': Same physical mechanism produces vocalizations in elephants and humans." ScienceDaily. www.sciencedaily.com/releases/2012/08/120802141527.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Feast Your Eyes: Lamb Chop Sent Into Space from UK

Feast Your Eyes: Lamb Chop Sent Into Space from UK

Reuters - Light News Video Online (Nov. 25, 2014) Take a stab at this -- stunt video shows a lamb chop's journey from an east London restaurant over 30 kilometers into space. Rough Cut (no reporter narration). Video provided by Reuters
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


Mystery of Elephant Infrasounds Revealed

Aug. 3, 2012 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 ... 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