It really is rocket science—researchers are using huge x-ray scanners from NASA to understand how sonar might be affecting the hearing of large ocean mammals. These scanners are usually used to inspect the space shuttle’s solid fuel rockets.

Navy sonar has been accused of harming the hearing of large marine mammals such as whales and dolphins. So Navy-sponsored researchers at San Diego State University and U.C. San Diego developed a method of using the NASA machines on whale skulls.

By scanning male beaked whale skulls, the researchers imaged the whale hearing apparatus in 3-D. Then they modeled how sound would interact with the anatomy. And then they investigated how that sound-anatomy interaction would be affected by sonar.

The computer model finds that mid-frequency sonar is mostly filtered out for the whales, while the higher frequencies the animals use for hunting appear to be unimpeded by sonar. Now they say they need to verify the system by testing it on animals such as dolphins, for which we have better hearing records. Scientists say this technology could allow a peek—or an eavesdrop—into how all sorts of marine creatures hear the world around them.

—Cynthia Graber

[The above text is an exact transcript of the audio in the podcast.]