The loneliest whale refers to a particular whale call at 52 hertz (Hz) that has been recorded regularly in the northern Pacific ocean, along the western coast of North America, since the 1980s.

Sorry, let me back up.

All whales use sound to communicate with each other. Sound travels much farther in water than in air, you see, which makes it possible for the gentle giants to sing to one another across vast distances. Each species of whale sings at a particular frequency, measured in hertz - the number of peaks (or troughs) in the sound wave per second. The largest animal ever to exist, the blue whale, vocalizes at frequencies between 10 and 39 Hz. Fin whales sing around 20 Hz. The loneliest whale follows the migration pattern of blue and fin whales and yet sings like neither of them.

You can listen to a version of its call here. It's been sped up by 10 times, to 520 Hz, so that it falls within the human range of hearing.

What must it be like? To understand but not be understood in return, no matter how hard you try?