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.
The short answer is, BLUE WHALE is the HEAVIEST animal to ever live. AMPHICOELIAS fragillimus (sauropod dinosaur) was the LONGEST animal to ever live. SAUROPOSEIDON proteles â¦(sauropod dinosaur) was the TALLEST animal to ever live. The term large could be defined in terms of weight, length, or even height.