Rocky Raccoon's tail looks like it's just the fur gone not any skin, so it should be OK. He might have got it caught in something and pulled out the hair when getting loose. If it were mange, you'd expect to see some hair loss elsewhere not just the tail, but it could be.
Today, the evil squirrel wanted to come down from the oak nextdoor. Tornado-dog was not having it. It was a standoff for about 15 minutes before squirrel decided not to chance it...