The songs of beaked whales in the deep sea have long been a mystery. But now, thanks to an advanced undersea glider that drifts through the ocean depths silently, scientists are listening to their arcane music for the first time.

Although undersea gliders have been around for about a decade, this is the first time one has been equipped with specialized acoustic devices designed to study marine life. State-of-the-art software is capable of distinguishing beaked whale noises from the cacophony of other ocean sounds.

Because the gliders can dive to depths of over 1,000 meters, the machines can gain access to a majestic undersea world not available to traditional acoustic devices on the ocean surface, and they can do so without making much noise. That silence is important, since it means the gliders have the potential to get up close and personal with the shy cetaceans.

Scientists also hope to glean clues about beaked whales, who are extremely sensitive to man-made noise, and why they are driven to beach themselves when in the presence of military sonar equipment.

The $1.5 million project, funded by the U.S. Office of Naval Research, began back in 2007, but significant results — as published in Nature — are now beginning to surface. "We believe we have identified beaked whales," said Oregon State University's whale-acoustics expert, Dave Mellinger. "It was pretty exciting. You work a couple of years on a project, hope it will succeed, but you don't know until the equipment is wet."

Beaked whales like to spend time down deep. They can dive to depths greater than 2,000 meters and have been known to stay underwater for as long as 85 minutes. Due to their remote habitat, the population status of 16 of the 20 species of beaked whale is entirely unknown, though many are thought to be endangered. Rising levels of toxic chemicals have been found in their blubber, and they seem to frequently ingest floating trash and plastic bags, likely mistaking them for jellyfish.

Hopefully by listening to their cryptic songs, scientists can begin to learn more about these grandiose beasts of the deep.