"The Grinch's body is a sort of huge, sagging, pear-shaped structure, with arms, legs, elbows, and bony knees not unlike those of the Coyote. In fact, Dr. Seuss felt that my Grinch looked more like me than like his Grinch. Like all fully animated characters, the Grinch has an implied skeletal structure and muscles; once decided, his skeleton had to be respected, to avoid rubbery inconsistency and unbelievability.
"The Grinch's dog, Max, has a much bigger role in the film than in the book, because we needed a character to be both victim and observer. Max was directly inspired by a sad little fox terrier my father once tried–and failed–to train.
"To some extent we are all Grinches about Christmas–all that noise, all those unwanted presents, all those thank-you notes to write.
"Whenever I rented a car around the time [Dr. Seuss'] How the Grinch Stole Christmas! first appeared on television, it was invariably Grinch-green, which was a popular color for cars at the time. I didn't like it, and frequently had to upgrade to a more congenial color. The Grinch himself changes color slightly, turning a friendlier green when he has his change of heart."
–Chuck Jones, Chuck Reducks, Drawing From the Fun Side of Life