The head of the sugar glider is uniquely shaped. I have heard some people say that it looks similar to that of a bat, some even say that it is similar to that of a cat. Either way, the head is, for the most part, small and oval shaped.
Some sugar gliders have a longer more pointy nose while others have a shorter, stubbed nose.
If a sugar glider from another colony is detected, a fight will most likely break out to run the intruder off.