The World's Loneliest Whale

He's called the loneliest whale in the world and for three decades he has crooned his way around the Pacific, his songs drifting into the depths, unheard and unrequited. He's known simply as "52" bcause he emits his calls at a frequency of 52 Hertz - a pitch no other whale can understand. Josh Zeman is an American film-maker and is joining up with a team of scientists to make a documentary about 52.

(Photo: Whale coming to the surface. Credit: Thinkstock.)