151st ASA Meeting, Providence, RI

Horse Whinnies: The Search for Specific Equine Vocal Expression

David G. Browning - decibeldb@aol.com
Department of Physics
University of Rhode Island
Kingston, RI 02881

Peter M. Scheifele - peter.scheifele@uconn.edu
Department of Animal Science
University of Connecticut
Storrs, CT 06209

Popular version of paper 5aABb7
Presented Friday morning, June 9, 2006
151st Meeting Acoustical Society of America, Providence, RI

Acoustic research can provide ways to evaluate and improve the quality of life for domestic animals, as it already has for humans, but we have some catching up to do, whether it be evaluating hearing loss in dogs or determining any relation between stress and vocalizations in horses.

We are collaborating on a two-pronged effort, with results from both aspects being reported at this meeting. Paper 3pAB4 deals with canine hearing/audiology while this paper (5aAB7) investigates any connection between equine vocalization and stress.

The Equine Vocalization Project (EVP) is a modest introductory research effort to acoustically analyze the vocalizations of Equines (horses, donkeys, and zebras) and to determine if there are any specific vocal expressions connected to stress.

The vocalizations of many domestic animals consist primarily of a few simple tones. For example, the "moo" of a cow has an acoustic spectrum very similar to a simple party horn.

The vocalizations of the Equines (horses, donkeys, and zebras) can be more complex with a wider bandwidth and varying frequency.

This allows, at least acoustically, the intriguing possibility of specific vocal expression.

A study of donkey brays, however, indicates that as acoustically rich as they are, a donkey simply "lets them rip" with no apparent control of their content.

Present interest centers on the unique whinny of a horse.

It is generally accepted that horses, at least visually, have an excellent perceptive ability - such as recognizing specific people.

The quest now is to determine if horses can utilize this with their vocalization ability to produce specific vocal expression.

So far we have learned several things, namely that a whinny consists of two elements: a variable frequency component and a frequency shift component which can be associated with the horse's state of excitement.

Under high-stress conditions, for example stallions fighting, the whinny does appear to degenerate to a uncontrolled high-pitched scream.

But under calm conditions and especially under visually restricted conditions, for example when a another horse is heard entering the barn but is out of sight, the whinnys appear to have a rich and variable content.

These calm conditions will be the basis for further measurements.

Our "secret weapons" for this project are all the many experienced horse riders in our region (for example, it has been stated that Connecticut has the highest density of horses - one for every 68 people - in the country) that can provide essential feedback and information for our study.

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