Geophysicist Milton Garces uses infrasonic recording technology to listen in on activity in Kilauea’s lava tubes.

Milton Garces records infrasound in order to understand what's happening in Kilauea's underground lava tubes. Read the interview.

Humans can't hear infrasound, which scientists define as any sound pitched below 20 hertz to as low as 2 hertz. But it turns out that some animals, including elephants, hippos, giraffes, whales, and alligators, have acute infrasound hearing.

In recent years, new techniques and technologies have allowed scientists to listen more carefully -- and realize that giraffes may be talking after all.