The Avatar director claimed that Steven Spielberg beat him in a race to secure the screen rights to Michael Crichton's novel by "a few hours", and went on to make a film vastly different to the one he had envisioned.
"When I saw [Jurassic Park], I realised that I was not the right person to make the film, [Spielberg] was. Because he made a dinosaur movie for kids, and mine would have been Aliens with dinosaurs, and that wouldn't have been fair," Cameron told The Huffington Post.
"Dinosaurs are for 8-year-olds. We can all enjoy it, too, but kids get dinosaurs and they should not have been excluded for that. His sensibility was right for that film, I'd have gone further, nastier, much nastier."
Cameron has recently been discussing the process of writing his Avatar sequels, saying that he wants to avoid the problems faced by the Matrix follow-ups.
"It's a little bit of a daunting writing task because it's two scripts and they've both gotta be done at the same time," he said. "I'm writing it as separate stories that have an overall arc inclusive of the first film. I don't want to suffer from the Matrix 2 problem, where it just ends, like, what the hell? It's gotta end.
"There's gotta be a sense of conclusion, but also a sense that the journey will continue, and that's a fine line."
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Cameron's 1997 blockbuster Titanic was released on 3D Blu-ray for the first time on Monday (September 10).