I think it's a dinosaur.
The largest animal ever is the blue whale ...although it didn't quite walk on earth. http://en.wikipedia.org/wiki/Largest_organisms
If you've ever seen one (I have) then there is no doubt it's the largest animal on earth.
The Blue Whale is the largest animal to ever exist.
The Blue Whale is the largest cetacean, and is also the largest animal ever to have lived on earth.
the blue whale (answer by karl )
The largest animal that has been to space is a human, with the common chimpanzee coming in a close second.
Was and still is the Blue Whale
I do believe that the megaladon's teeth were indeed the largest, since it was the largest animal ever to exist on this Earth.
Blue whale. The largest organism, by size, is a single fungus in the Pacific Northwest.
Nothing. The blue whale is the largest animal ever to live on earth.
The largest animal ever captured and held in captivity is the Killer Whale (Orcinus Orca).
Yes, the blue whale is the largest animal that has ever lived on Earth.