All animated films begin as a series of drawings. Each character is drawn in every conceivable pose and from all angles again and again. Once the drawings are complete they're compiled in a fashion similair to a flipbook. However, unlike a filpbook, which may have 20 or 30 drawings, one minute of animation contains approximately 1,400 drawings. As animated features are roughly seventy minutes long, aproximately 980,000 drawings are created for an animated film.
The number of drawings requires a great many artists to collaborate on drawing a single character. Great attention is given, so that even though 25 people participate in the production of a single character, that character's looks and moves are consistant thoughout the film.
Balto took three years to make and was the effort of over 250 people. To learn more about how animated movies are made check out the process.