Humpback whale in Cierva Cove, Antarctica

© Robert Harding World Imagery/Offset

Humpback whale in Cierva Cove, Antarctica

An adult humpback whale is roughly the size of a bus and its tail fin, called a fluke, can be five metres wide or more. Most of the time, surfacing humpbacks crest above the water simply to take a breath. They are mammals and can’t breathe underwater, so they emerge to breathe deeply through their blow holes before diving again. But from time to time, humpbacks breach. That is, they propel themselves almost entirely out of the water and belly-flop back in. Scientists still aren’t sure exactly why humpbacks do this. It could be a hunting method, a way to clean themselves, or (our favourite hypothesis) simply for the fun of it. And let’s join this humpback in celebrating World Oceans Day today, by paying respect to the 70 per cent of the Earth’s surface that isn’t dry land.