Darren Naish: To begin with, let's get things straight and admit up front that Godzilla is not a real animal, nor was it ever. It's an unfeasibly big late-surviving dinosaur (belonging to the hypothetical taxon Godzillasaurus, according to some), mutated by radiation, with a radioactive heart, and virtually impervious to other gigantic monsters, robots, artillery, laser blasts, lava and fire. Not real. Sorry about that. But by posing questions about fictional entities we can still learn stuff, and you may be surprised to learn that Godzilla has, on occasion, been discussed semi-seriously by various biologists and palaeontologists. Ok, that won't surprise you if you already know anything about Godzilla, but what the hey. If you fundamentally object to the coverage of fictional entities (after all, there are more than enough real tetrapods to right about), then feel free to ignore this post and wait for the next one... A little bit of introduction to Godzilla first. To date Godzilla - and here I mean the real Godzilla, and not the thing that appeared in the 1998 TriStar movie (known variously among Godzilla fans as Fraudzilla, Deanzilla [after writer/producer Dean Devlin], GINO* or Zilla) - has appeared in over 20 movies, dating from 1954 to the present. If you've seen any of the new films, you'll know that they don't follow on chronologically from their predecessors, a bit like the latest Bond film. The films are still being made, with the latest being Godzilla: Final Wars (2004). There is tons and tons of stuff about Godzilla on the internet, of course.