In 1989, scientists at Woods Hole Oceanographic Institution heard a sound coming from their audio equipment they hadn't heard before. They had heard whale sounds many times, but this whale sounded different. They weren't able to tell what species of whale it was, but they kept listening as it drifted away into the dark abyss of the ocean and fell silent.

In 1992, they found this unique whale sound again and they have tracked the whale since then. The US Navy’s sophisticated billion dollar hydrophone system, designed to track Soviet nuclear submarines during the Cold War, has recorded the whales migratory patterns every year as she moves from central California to the Aleutian Islands in the north Pacific. Though they can track her, no one has ever seen her in the wild. They aren't even sure what species of whale she is.

She has always traveled alone, and according to a report in the Deep Sea Journal, her migration is "unrelated to the presence or movement of other whale species." She has no family, she isn't part of a pod, she's never had a mate, in fact, she is always by herself. And yet, as she makes her way through the vast oceans, she calls out, searching and waiting for an answer, or a companion that never comes.

She's now called the 52-hertz whale, or what most folks call her, the loneliest whale in the world. Because of how long she's been monitored, and how far she travels, scientists think she's in good health. But whales are social creatures, and her isolation has taken a toll.

Whales vocalize at 10 to 39 Hertz, but the loneliest whale in the world speaks at 52 Hertz, just higher than the lowest note of a tuba. That's what makes her different. It's what makes her unique. It's also her curse and what keeps her alone. The other whales can't hear her. They don't know she exists. Her cries go ignored, and her pleas go unanswered. But she never stops trying. Her calls never fade. She never gives up hope.

Over the years, scientists have noticed her vocalizations have deepened, more like 49 Hertz now. They think it might be because of her getting older, or maybe she is trying to change the sound, because maybe she knows something isn't right.

Mary Ann Daher is a marine biologist who co-authored the original research on the discovery of 52. As the paper went public, more people identified with the whale’s hopeless situation, so much so they even wrote to Daher expressing their empathy.

And so, the loneliest whale in the world continues her search, and she waits for the day when her dream will be real and the empty feeling in her heart, will be full. On that day,  her quest for companionship will be over. She will hear, off someplace in the murky distance, the answer to her calls echoing through the sea. On that day, when her pleas are met with compassion and understanding, she'll be home, and lonely no more. =]:)