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Double Dolphin Sonar

July 11, 2011

Using precision instruments, scientists have discovered a second dolphin echolocation signal previously unknown to science.

Transcript

BOB HIRSHON (host):

Double dolphin sonar…I’m Bob Hirshon and this is Science Update.

Dolphins use echolocation to navigate underwater and hunt for prey. They bounce high frequency clicks off of objects to locate them. Until now, scientists believed that the marine mammals emit just one beam of clicks from a special organ in their heads. But a new experiment has detected a second echolocation beam, with different frequency clicks. Researcher Josefin Starkhammar of Lund University in Sweden says the second signal makes sense for survival.

JOSEFIN STARKHAMMAR (Lund University):

When the dolphin is hunting fish, it would be good to be able to surround the fish with sound more, it would be easier for it to locate the moving target if it had two beam projections like the ones we have found now.

HIRSHON:

She says in contrast, echolocating bats have only one signal, and have to constantly move their heads to the right and left to locate their prey. I’m Bob Hirshon, for AAAS, the science society.