Making static creatures and objects move is an animator's job. When making an action sequence, she positions the creature by moving the bones within its mesh. She sets up key poses, and the computer fills in the others according to a formula Jones selects. But people are important models, too. You have to be sure you're moving the muscles in a realistic way.
Animation is more than creating natural motion, though.
It takes skill in dramatics. Using facial expressions and body language, animators imbue characters with personalities, says Jones. If I'm working on a scene with a lot of dialogue, I play the recording track many times. I'm listening for the words and inflections. I want to understand the emotions behind the movement in the scene.