Which is the largest mammal?

The blue whale is not only the largest mammal but the largest animal ever known to have existed, surpassing even the biggest dinosaurs. It can grow up to about 30 metres long and weigh as much as 150 to 200 tonnes, roughly the weight of dozens of elephants. Its heart alone is about the size of a small car, and a human could theoretically swim through its largest blood vessels. Despite this immense size, the blue whale feeds almost entirely on tiny shrimp-like creatures called krill, filtering enormous quantities from the water through baleen plates. It can consume several tonnes of krill in a single day during feeding season. Hunted nearly to extinction in the 20th century, blue whales are now protected, and their populations are slowly recovering in some regions.