A New Song

Blue whales are hidden giants. They’re the largest animals on the planet. But they’re shy, and they inhabit some of the most remote locations on the planet, so they’re hard to spot. Yet researchers recently found a new group of them. They didn’t actually see any of the whales. Instead, they heard their “songs” in recordings made over the last couple of decades. They sped up the recordings to make the calls easier to hear.

Each population of blue whales produces its own unique songs. The songs can travel hundreds of miles.

Researchers reviewed recordings made by a network of underwater microphones. The network listens for evidence of nuclear-bomb tests. But it also records other undersea sounds, including whale songs.

The researchers found a song that no one had heard before. It consists of three parts, lasting a total of about three minutes. They called it the “Chagos” song because it was heard around the Chagos Islands, in the central Indian Ocean. It was heard as far away as Australia, though, indicating that the whales cover a large range.

The song is similar to that produced by several populations of pygmy blue whales. They’re the smallest of all blue whales -- about 80 feet long. The researchers concluded that the new song is produced by a previously undiscovered population of pygmy blue whales.

No one knows how many of the whales there are. But the recordings provide strong evidence that a new population of hidden giants is gliding through the Indian Ocean.