On his blog, David Petersen shares images from and commentary on the Mouse Guard sketchbook, a limited release he sold at cons before the first color Mouse Guard mini-series began. His comments on the art also hint at how the story evolved before it was released:
Mouse Guard started as a different story with many species of animal, including wolves. So when the mice became the focus of the stories I wanted to tell and the rest of the world became a backdrop that the mice never want to see, the wolves became backdrop as well. However, I included their presence in the end of the Fall series beyond the mysterious ’scent border’. I don’t know exactly how Sadie is going to fare against this beasty, but I do like the idea that a skilled Guard could take down a lone wolf. I have more plans for the wolves and the ’scent border’ in future MG series.

