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.
Blue whales evolved back into the sea from land mammals, in “one of the most dramatic transformations in mammalian evolutionary history”. The land mammal was the pakicetus, which looked like a possum’s head sewed on to a stray rat-dog’s body by a twisted butcher in a slimy Eocene cave. No wonder it decided to move back to the ocean.
The blue whale-to-be returned to the water as dorudon, 4.5 metres long and with a tail that moved up and down, not side to side. Then it grew and grew and grew, eating krill – eating trillions upon trillions of fullstops worth of sleep.
The sperm whale’s brain is the largest of any animal. The blue whale’s heart, the size of an armchair, beats, on average, once every 10 seconds: much more slowly when diving, faster at the surface. Blood rushes through its veins and the whale’s enormous body shakes slightly.
“Weeks I couldn’t sleep. Years I couldn’t waken,” writes David Baker in his poem Whale Fall. The title is the term for a dead whale that sinks to the bottom of the ocean, where it creates an entire ecosystem – a world, a galaxy – that can last for more than a century. The whale’s carcass rests on the sea bed; the living whale rests on nothing. Far, far above them Ishmael climbs under the covers:
With the landless gull, that at sunset folds her wings and is rocked to sleep between billows; so at nightfall, the Nantucketer, out of sight of land, furls his sails, and lays him to his rest, while under his very pillow rush herds of walruses and whales.
Helen Sullivan is a Guardian journalist. Her first book, a memoir called Freak of Nature, will be published in 2024
Have an animal, insect or other subject you feel is worthy of appearing in this very serious column? Email helen.sullivan@theguardian.com
