WHEN Terry Notary starts sniffing the microphone and making monkey noises you begin to wonder if working on the new Planet Of The Apes movie hasn't left him permanently scarred.

He assumes the facial and body posture of the primates he studied in preparation for teaching the actors in ape school. You half expect him to leap from his chair and start swinging from the ceiling light fittings.

The agile stunt player and former Cirque du Soliel performer was recruited by the makers of the 2001 re-imagining of the 1968 movie to teach the actors to be ape-like. Make-up would make them resemble apes, he had to teach them to move like them. "You have to re-learn everything," he explains. "To really be an ape you shouldn't act like an ape, you have to get into their headspace. When I got this job I was not an ape specialist. I had to do some research to find out where the ape was going to come from."

He played with chimps and observed apes in zoos, developing a series of basic movements and some that were specific to different species as the film features gorillas and orang-utans as well as apes.

He says: "The first thing I wanted was for the actors to get back to being simple. If they wanted to smell something, then smell it. It's really just letting everything go."

Some actors were better than others at going ape. Helena Bonham Carter, who plays human-friendly ape Ari, was bottom of the class. "After the first week we had an evaluation and I said Helena needed a lot of work," recalls Notary, adding that the actress finally got it right.

Pupils wore their ape hands and teeth during classes to get a feel for the costume. "We would have them come in and play in the make-up, look in the mirror and make faces. That helped as far as letting go goes," he says. "You have to feel free and open to express."

British actor Tim Roth, who plays the villainous ape general Thade, was a star pupil. "He took to it and loved it. He had a hard time getting the hip movement, then after two weeks he came in and boom it was there."

Director Tim Burton wanted his talking apes to be 20 per cent ape and 80 per cent human. Human traits, such as eating, drinking out of glasses, using weapons and riding horses, were mixed with more usual ape behaviour.

"When they freak out they are 100 per cent ape," he adds. In the battle scenes, apes are seen running at speed on all fours or quadrapeding as Notary puts it. "We had a huge audition and came up with 20 guys who could run on all fours - strong gymnasts are the ones that can do it, usually short guys like myself." Notary is seen as a quadraped running alongside horses in the climactic fight with the humans. He stunt doubled for Tim Roth and played four other characters. He also had to choreograph the crowds in the Ape City sequences. The hard physical nature of the work meant injuries, mainly from sore legs and backs. Another hazard were the real chimps used in the film. One tried to bite Notary on the ear. "They are the cutest things in the world, then they just turn. They are 50lbs but solid. If they get scared, they can turn on a dime," he says.

Planet Of The Apes (12) is now showing in cinemas.