very low frequency

"When the whales push air from their lungs past this cushion, it starts to vibrate and this generates very low frequency underwater sounds."

"Our experiments showed for the first time how the whales make their very low frequency vocalizations," says Elemans.

The mammals' signature, very low frequency song could be heard primarily during March and April.

Now, researchers say the bird may hitch a ride by listening for very low frequency sounds humans can’t hear—one of only a few species known to do so.

Researchers tracking the paths of these long-distance fliers report today in the Proceedings of the National Academy of Sciences that the very low frequency noise made by clashing waves influences the birds’ headings.