The blue whale is the largest animal that has ever lived

The blue whale (Balaenoptera musculus) is not just the biggest animal alive — it is the largest animal known to have ever existed, outweighing every dinosaur in the fossil record. NOAA reports they reach about 110 feet long, longer than a basketball court.

Antarctic blue whales can weigh up to 200 tonnes. Their proportions are almost hard to picture: the heart alone weighs roughly 400 pounds — about the size of a small car — and a single beat can pump tens of gallons of blood.

They sustain that bulk on some of the ocean’s smallest prey, swallowing up to 3,600 kg of krill a day during feeding season.

Despite their size, blue whales were hunted to near-extinction in the twentieth century and remain endangered today, which is why so much of what we know comes from conservation science rather than casual observation.