In all my years of riding I can only think of one incident where I was involved with hitting an animal... we were racing in a criterium and a dog walked out right in front of the pack I was in, front rider went down along with most of the rest of us. The got up and walked away, several of us went to the hospital. One thing about squirrels and other wildlife is when they are threatened they go into an automatic panic mode which doesn't always get them out of harms way.

Aaron