Blue whales are the largest animals known to have ever existed on Earth - heavier than any dinosaur or extinct sea reptile we’ve found in the fossil record. A fully grown blue whale can stretch to 100 feet long and weigh 200 tons. (Some of the biggest sauropod dinosaurs may have come close in mass, but blue whales still win by a clear margin.)
The numbers around their bodies stop making sense. Their tongues alone weigh about as much as an African elephant. Their hearts are roughly the size of a small car - and you could fit through their main artery. About 50 people could stand on one blue whale’s tongue at the same time.
Despite their size, blue whales eat almost the smallest thing in the ocean: tiny shrimp-like animals called krill. They swim through clouds of them with their mouths open and filter them out with hairy plates called baleen. To stay this big, a blue whale eats around 4 tons of krill every single day.
