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 largest mammal is the Blue Whale which lives in the ocean and can grow to over 80 feet long. The largest land mammal is the elephant followed by the rhino and the hippo (which does spend a lot of time in the water). The smallest mammal is the Kitty's hog-nosed bat.