Suger Glider tail

Question
I have 2 male suger gliders, neutered both about 8 months old.  They are in a 3 foot by 3 foot cage, safe wheel, toys, 1-2 sleeping pouches.  I feed them glider complete from www.exoticnutrition.com.  I also sometimes feed them green grapes and crickets from that same website.  (grapes are from the local store).  One joey is slightly bigger than the other squirrel, his face looks fuller and more like most pictures i see on the internet.  I used some suger glider dry shampoo on his tail and felt it for bruises or bite marks bit it feels just like the other joeys tail minus some of the fur.  There are no completely barren spots on his tail, it just looks kind of scraggily.  He is a bit more timid than the other joey but still active and curious.  No real behavior changes...

I'm just a tad worried that he or the other joey might be biting or scratching the other one or himself while im sleeping.  I spent a few hours observing them I notice they inspected each others tails but no real agressive actions towards themselves or the other one.  They greeted and inspected each other and when tired would both retire to the same pouch they always sleep in.

My concern is that I noticed this evening that the smaller Joey's tail looks like it's missing fur.

Answer
if you are concerned that they are fighting you can try to separate them into two different cages and see if the fur comes back onto the tail and if it doesnt and fur keeps continuing to be missing there may be a medical problem....if the fur does grow back and starts to look fine then they were probably fighting or arguing about something when you werent there.....