LOS ANGELES (AP) – The set of “Two Brothers” was like a reverse zoo: The tigers roamed free while the humans paced back and forth in cages.

The sweet-natured story from director Jean-Jacques Annaud, who made the 1988 wildlife drama “The Bear,” chronicles two tiger siblings who are reunited in adulthood after being snatched into the human world.

But tigers can be more fickle than even the most temperamental Hollywood A-lister – these feline actors will LITERALLY chew up the crew if provoked. The only way to let the adult tigers feel relaxed enough to showcase natural emotions was to cage their prime distraction: humans.

“We went under the principle that tigers are extremely dangerous predators, that they are in some ways unpredictable – especially when they look so tame and so nice,” Annaud told The Associated Press. “We never forgot that tigers can be trained but never tamed.”

The movie also features “Memento” star Guy Pearce as a hunter and treasure collector who learns from the creatures that humans can be more deadly than the animals they fear.

When Pearce arrived in Cambodia, he was taken to the set to observe a tiger rehearsal. “The first thing they did when they got me out there was stick me in a cage. I found the whole thing deeply ironic,” he said.

Although dozens of cats played the two leads for stunts, long shots and stand-ins, the same two animals were used, as kittens and then nine months later as adults, for the closeups and intimate shots.

They were Kumal and Sangha, named after their characters in the movie. They now reside together at a naturalistic zoo in the Puy Du Fou park in France.

“They have at least 50 different expressions,” Annaud said. “What I didn’t realize when I started this movie is that tigers are creatures that can show so many nuances of emotion on their faces.”

The tigers were less of a danger when young, about 4 months old. They could interact safely with the human actors in most scenes, and Pearce even lets one nibble harmlessly on his hand in one sequence.

“They’re very much the same as a domestic cat. They’re moody, they want to play, they want contact, and if they get fed up with something they’ll swat you with their claw and let you know,” Pearce said. “I definitely got a nip every now and then … and one of them bit me on the shoulder, gave me a scratch. It kind of hurt, but I thought for the rest of my life I can say, ‘I was bitten by a tiger.’ It didn’t scar, which I was a bit sad about.”

The adult tigers were the real danger – the movie’s theme is that these creatures should not be hunted out of fear, but should be avoided out of respect.

The filmmakers cordoned off several acres of Cambodian jungle with fence and netting to keep the trained tigers from wandering too far into the wilderness. Then about five or six human cages, which could contain around 100 people, were set up around three to four remote-controlled cameras.

Once all the people were safely locked away, the tigers were set loose. A few trainers would try to guide their movements according to the script, but Annaud said the animals preferred to improvise.

“Tigers are very much like when you shoot something with children. You have to let them reinvent the scene by themselves by organizing the set, the props, even the light,” the director said. “You have to let the camera run.”

No one was hurt during the production, and the tigers did not try to attack. Sometimes, however, one would nudge repeatedly at a cage – a perpetually denied request to be let inside.

“Believe it or not they love small places – so any small enclosed space is appealing to them,” Annaud said.

The acres of natural wandering space also became an occasional problem for the trapped humans.

“The perimeter was quite large and about once a week a tiger would decide to take a walk around and would hide in a cave or bush. In a way, one of the rules is we don’t want to upset our stars – it’s very much a Hollywood rule,” Annaud joked. “So we would have to wait until they were finished having their good time. We were trapped in our cages and no one could move.”

Usually, he said, this happened at the end of a long day of shooting – so the people would spend long portions of the night waiting while the trainer tried to coax the tiger back to its trailer.

Pearce asked to do one scene with an adult tiger, but he said it was brief and required him to stand close to an open cage. “If the tiger was going to do anything wrong, (the trainers) were going to shove me in,” Pearce said.

There were additional precautions: “It was an extraordinarily reliable tiger. It was a sunny afternoon with no wind,” Annaud said. “The tiger had lunch twice and we gave him large portions. And there were two trainers on each side of the frame. I was so happy it worked very nicely, but I will say my heart was pumping.”