March 18, 2008

Scientists Discover Sounds Made By Baby Whales

Researchers at the nonprofit Cetos Research Organization have shown for the first ever that humpback whale calves make sounds.  

The organization studied the whales off the coasts of Maui and Kauai, and said the squealing noises made by the young whales are messages to their mothers.

However, the sounds are not as complex as the continuous, repetitive and highly structured sounds made by the older male whales.

Ann Zoidis, the project's research director, said the sounds made by the whale calves could be either warnings of threats of danger, or may simply be expressions of curiosity.

According to the study, the calves produced a limited number of sounds that were short and simple in their structure and included repetitive grunts that increased in strength. The sounds were sometimes accompanied by bubble streams and appeared to function as an alarm call to the mother.

They researchers said the sounds occurred more frequently when the mother was at rest, or during periods of slow travel.

"This tells us that calves do in fact communicate, and it tells us they are communicating to their mothers," Zoidis said, according to an Associated Press report.

The research was conducted between 2004 and 2008. Prior to that, scientists had recorded sounds from whale pods that included calves, but had difficulty determining precisely which animals were responsible for the noises, Zoidis said.

She said the common belief among most scientists was that humpback calves did not produce sound.   However the Cetos researchers were able to trace the sound back to its source, and demonstrate that both male and female humpback calves do indeed make noises.

The group is now continuing its work in studying the sounds, including when they are emitted, to determine whether they are a stress indicator.


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Cetos Research Organization

The study was published in the March issue of the Journal of the Acoustic Society of America.  A summary can be viewed here.

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