Brushless

Daily I have a grey squirrel who visits the feeders. I don't mind it coming. He/she usually comes in the morning. Today this squirrel came later in the afternoon. It seemed smaller and I wondered if it was a young one but eventually I realised that it didn't have the usual squirrel brush. Its tail is completely without hair and the end is very red and looks swollen.

I can't think what could have happened, I hope it wasn't damage by humans. You hear of youngsters doing such horrible things to animals. Other than that anyone any ideas as to what could have happened.