A whale: sleeping vertically, they look as though they could stop time | Helen Sullivan

Blood rushes through its veins and the whale's enormous body shakes slightly

Blue whales are the largest animal ever to have lived - including the dinosaurs - which also makes them the largest animal ever to have slept. All that sleep! A whole whale's worth, in vast, cold water, the ocean a closed eye, salty and dark. To watch a whale sleeping is to feel as though they have turned the world around them into sleep, that they are suspended in sleep itself, in the liquid that fills your bones when you turn off the light.

Sperm whales sleep vertically, in groups, suspended impossibly, the way an object might be suspended only in a dream. They look like planets, their orbit suddenly stopped. They look as if they could stop time. And maybe they would, if they ever slept for longer than 20 minutes, or closed both eyes.