I have a four month old girl. Two days ago I took her out of the cage she's been living with and put her in a smaller cage alone. This is temporary. I'm trying to move her from her original cage (my sister's cage) to a new cage (my cage). I'm sleeping right next to it so she at least has me here.

The reason I need her alone for a bit is because she smells like the male (Aang) from her cage. I want her in my cage, but the male that lives in it (Finn) is very territorial and I'm afraid her smelling like Aang is the reason he's aggressive towards her. Yes Finn is neutered and Aang is neutered as of today.

Now to the hissing sound! It starts off as hissing and then turns into a strange sound similar to crying. not like a Joey crying, but like a human sobing.Finn did a similar sound once after his cage mate died. She even does it when I hold her. She doesn't do it while going to the bathroom. Is she sad because she's alone? Is there anything for me to be worried about?

My best guess would be that she's feeling lonely and missing her cage mate. She's probably calling out to him. Since it's a temporary situation, I wouldn't worry too much and would spend as much time with her as you possibly can.

Is there anyway to help her not feel lonely at night when I'm sleeping?

Since gliders are nocturnal, they are most active at night. So they need a lot of stimulation and activities. A variety of toys and an exercise wheel are extremely important. I just recently bought a ball pit that has become the most favorite playtime activity ever! Pouches are also important so she has private place to rest and snuggle. If you hear her make sounds at night, it would probably be reassuring to call out to her to let her know that you're close.

I have toys, a wheel, and am currently sleeping right next to her cage. Everytime she makes the noise I put my hand on the cage.
She still does the hissing noise. I want her to be happy.

Sounds like you're doing all the right things. It's obvious you love her very much. The only other thing I can think of until you're able to reintroduce them, is to make an appointment with your vet to rule out any health concerns. They may have some helpful suggestions as well.

Mine do that. It's because she calling out to another glider. It's like they know there's one around and calling for them. They get very lonely ando need another one.

www.facebook.com/CreatedMoments/ Bonding buddy will give her something glider safe to snuggle with, you can also use them for scent swapping if you get two to help her and the male get adjusted to each other before introductions