The Titanic director called on stars including Sigourney Weaver and Zoe Saldana to get a feel for rainforest life, so they could better play their jungle-dwelling characters in the film.
He tells Entertainment Weekly magazine, "We did a sense-memory experiment in Hawaii. We trekked around the rainforest for three days, building campfires and cooking fish, trying to live tribally."
And Saldana insists Cameron's pre-filming jungle expedition was a great idea: "That experience helped us so much. Sigourney, Sam and I were shooting the movie on a regular cement floor on a soundstage, but we needed to know what it was like to walk in a jungle world, what that felt like."