Blue Whales are the largest animals ever to exist, EVER. Find out more about these amazing creaturesBlue whales are incredibly, incredibly large. Measuring 100 ft long and weighing in at 190 tons, Blue Whales are the largest known creatures to exist, ever. Even the largest known dinosaur Argentinosaurus only clocked in at 99 tons—a little more than half the size of a full grown blue whale!The