what's the biggest animal in the water
of 21. Biggest Whale - The Blue Whale (200 Tons) The Blue Whale, the world's biggest whale. Wikimedia Commons. At about 100 feet long and 200 tons, not only is the Blue Whale the biggest mammal in the world today, but it's the largest vertebrate animal in the history of life on earth: not even the largest dinosaurs approached it in bulk.