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 blue whale is easily the largest animal on Earth. See more pictures of marine mammals. By considerable measure, the largest known animal on Earth is the blue whale. Mature blue whales can measure anywhere from 75 feet (23 m) to 100 feet (30.5 m) from head to tail, and can weigh as much as 150 tons (136 metric tons).