I believe stemardue is correct. Next time you watch a short animation film, check the credits. When we started our big animation project, we got in contact with Sony Pictures, and chatted with the project manager of "The Chubb Chubbs". She told us what programs they used and what was involved in undertaking the project. She said the reason why there were so many animators was because the animation becomes micro-managed. She said that an animator may be dedicated to a single emotion, or single type of clothing. I found this to be kind of funny. Could you imagine telling people, "Yeah so I am the angry guy!!"... lol