The number one spot for the world's largest animal, goes to the Blue Whale… This massive animal weighs up to a crazy 200 thousand to 300 thousand pounds and is over 98 feet long… Despite their name being the Blue Whale, they aren't actually blue, they are gray... While also being the largest animal, they are also the loudest animal too. They can produce calls up to 188 decibels… Most blue whales can actually live up to 90 years old.