Steve Zahn went ape over latest role

With “War for the Planet of the Apes,” Steve Zahn has landed the biggest part in the biggest film of his career. There’s only caveat: He doesn’t actually appear on screen because he’s playing a chimpanzee.

But he wasn’t just monkeying around. He chimp-walked through scene after scene of the production, his knuckles dragging and his knees bent so sharply that he needed Epsom salt baths to ease the pain every night.

“For six months I had to learn to quadruped, and my thighs became so strong it was unbelievable,” he said.

The movie, which opened Friday, was done in motion capture, a procedure in which actors’ bodies are covered with dots of tape. A computer uses the dots to create a representation of an object, in this case an ape. Because the actors weren’t restricted by bulky ape costumes, they were able to move much more freely, including running, jumping and, as the script required, tumbling to the ground.

“I went into this not really knowing anything about what motion capture was,” he said. “I was the most nervous I’ve ever been. I was petrified the first day.”

He quickly learned that there’s nothing phoned-in about this deeply technological form.

“When you see us quadrupeding together across a prison yard to get away from bullets, that’s exactly what we’re doing. In that location, too,” he said. “It’s not like we were in some studio with green screen, reacting to something that wasn’t there.”

When a scene shot in snowbound British Columbia looks like it was cold, it was cold, he said, and when it looks like they were in pain, they were in pain. Playing the ape characters had to become so secondary that they could focus on the emotion of the scene.

Zahn wore 51 dots on his face so the computer could convert his expressions to the face it was generating for his character. Zahn has a special gift as an actor with his soulful, expressive eyes, which allows him to speak volumes with a gaze. He was able to add that element to the character because “the camera is always recording you, at all times. Those dots on your face really record every movement and they can incorporate that. You can see even the tiniest expression through all that technology, every blink, every moment when I looked away.”

Although Zahn studied acting at Harvard and has spoken in movies as a pig, cat, shark, bear, chicken and dinosaur, prepared him for this role, he said.