Slate:

The whale that Joe George and Velma Ronquille heard was an anomaly: His sound patterns were recognizable as those of a blue whale, but his frequency was unheard-of. It was absolutely unprecedented. So they paid attention. They kept tracking him for years, every migration season, as he made his way south from Alaska to Mexico. His path wasn’t unusual, only his song—and the fact that they never detected any other whales around him. He always seemed to be alone.

So this whale was calling out high, and he was calling out to no one—or at least, no one seemed to be answering.

What a sad and remarkable story.