A blue whale's tongue is so heavy that it weighs as much as a whole elephant.

The blue whale is the biggest animal to ever live on Earth, growing up to 100 feet long. Its tongue weighs about 6,000 pounds (2,700 kg), which is the same as a full-grown forest elephant. This giant muscle is built to handle incredible pressure when the whale feeds.When a whale eats, it takes a massive gulp that can hold up to 90 tons of water and food. The tongue then pushes that water through 'baleen plates' which act like a giant sieve to catch tiny krill. Even though the mouth is huge, the whale's throat is only about the size of a grapefruit. This means it can only swallow tiny things like shrimp, not large fish or people.Scientists at the Smithsonian Institution have found that the whale's tongue is mostly made of dense muscle and fat. This helps it stay strong against the heavy weight of the ocean water. Moving such a big tongue takes a lot of energy, but it pays off. A blue whale can eat 8,000 pounds of food every single day to keep its massive body moving.The rest of the whale is just as giant as its tongue. Its heart is the size of a bumper car, and its blood vessels are wide enough for a person to swim through. Research in the journal Science shows that this unique way of eating is the only reason whales can grow to such a record-breaking size.