introducing a new glider

Question
how do i introduce a new female sugar glider with the 3 others i have that have been together for a very long time?

Answer
Amber,

Are the other gliders male or female? This could make a big difference.  

Here is my article about introducing gliders to each other:
Glider introductions can be simple or difficult, depending on the individual gliders.  Generally, the younger the better.  Two young females will bond easily, as will a young male and female. The only way to successfully bond two males is if they are siblings and have grown up together.  Introducing older gliders can be tricky, as their personalities and preferences are already set.  

Begin by putting the cages together and letting the gliders smell each other for several days.  Switch bonding pouches every day so their scents will blend together.  

When you are ready to see if they can get along, take both pouches into the bathroom.  Glider-proof the room and hang up some towels, pouches, etc. to provide extra hiding places.  Have a hand towel ready to toss over them in case they start to fight.

Put some vanilla extract on the back of their necks (like perfume).  Put both pouches in the bathtub or sink, with the openings facing each other.   At this point one or both of them will come out to see what's going on.  Just leave them alone, unless they make a fighting furball, in which case you'll need to separate them with the towel and try again another time.  They will sniff at each other, fuss, crab, and probably chase one another. Be patient.  Hopefully they will settle down together. If not, then you'll have to repeat the previous steps.  It takes a lot of time and patience, but, hopefully, it can be done.  

Good luck, please keep in touch,

Betty