Regarding Charlie and the Chocolate Factory

This is a quote about Charlie and the CHocolate Factory
"I also have to mention a remarkable scene in "The Nut Room." Burton found animal experts who actually succeeded in training 20 squirrels to shell walnuts while sitting on stools over a conveyer belt. Several more of the animals were computer-generated, and effects were used for some movements, but nevertheless squirrels, with their short attention spans, are extremely hard to train. Trust me: you've never seen anything quite like this."