We have had our Degu a little over a year now. He's very active, chatters alot, does not have issued eating or drinking and the other day I noticed the end of his tail did not have any hair on it. This happened very recently and seems very sudden. He does not seem to be in distress or does not mess with it. I have looked at it quite a bit and it does not seem irritated and I do not see any blood, bone, or cartilage to suggest an injury. He does run on his wheel alot but not any more that before. I have not changed any food, treats, or anything like that. We have recently moved him to a three story cage. I have tried reading everything I can and cannot seem to figure out what it could be. I have a picture but I am unable to attach it to my post. Any suggestions would be greatly appreciated.