The biggest sea creature in the world is the blue whale; it grows up to 110 feet long and weighs up to 441,000 pounds. It is also the largest animal known to have existed, surpassing even the dinosaurs in size. The blue whale belongs to the group of baleen whales, which feed on plankton and small fish by filtering them through their comb-like teeth. The blue whale has a huge heart that can weigh as much as a car and be heard from two miles away. The blue whale is endangered due to whaling and other threats.
