Wiktionary(0.00 / 0 votes)Rate this definition: mutant(Noun) Something which has mutated, which has one or more new characteristics from a mutation. mutant(Noun) Someone or something that seems strange, abnormal, or bizarre. mutant(Adjective) That has undergone mutation.
Best Answer: The Blue Whale, Balaenoptera musculus, is the largest mammal living today. It is also the largest mammal to have ever lived. In fact the Blue whale is the largest animal ever to have lived on the planet as far as we know; bigger by far than ever the largest Dinosaur.
View full size image. Diving to depths of 328 feet (100 meters) to munch on millions of krill each day, the blue whale takes the prize for the largest creature alive (and ever to exist!). These blue-gray giants extend about 80 to 100 feet (24.4 to 30.5 m) in length and weigh about 400,000 pounds (181,437 kilograms).