behavior question

[t3h_kyle]

Hi everyone,
I first adopted a pair of sister female rats and they have been perfect with each other and towards me. After having my first pair of sister rats (Moxxie and Mabel) I adopted another pair of sister rats (Riley and Riven); that i've had for around a month now. I did the quarantine and introductions and they were perfectly fine together; up until recently they started to show a change in behavior. They have been in the same cage together for a little over a week now, sleep together and everything; but when it comes to them at night Riley and Riven are somewhat aggressive towards Moxxie and Mabel and always chase them and get into little scuffles. Riley always chases around Mabel (and I mean ALWAYS) and Riven just started chasing Moxxie. I guess what i'm asking is if this is playing, bullying, or a dominance issue that will resolve itself. Thanks for helping!

Below is Mabel on the left and Moxxie on the right!
After that it's Riven on the far left (who looks terrified...), then Riley, then Moxxie, and Mabel on the far right!

 

[SterlingRats0408]

I have two girls that between 9-11at night play fight very loudly like clockwork!
It could just be play, the general rule...no blood no foul....Riven doesn't necessarily look terrified it could be a sleepy face or an annoyed face, you know your girls better then anyone but that face could be a few things.
Tyrion makes that face when he's being groomed, he whines but also bruxes!

 

[t3h_kyle]

I've noticed a scratch on Riley and that's about it.. Mabel has sidled her once that I've seen and they had some nose-off's but it's always Riley chasing her. They both are very loud when this happens and i'm just worried a little about it; when it becomes too bad I separate them usually for the night.

 

[jorats]

Sounds like the older girls are showing the young ones who's who in the colony. How old are all the girls?
Also, how big is the cage?

 

[SterlingRats0408]

Rat play can get very vocal...Smoosh squeals when Delphi finally pins her. I think of it like siblings fighting, yelling, wrestling, someone may cry but its just how the structure stays in their group.

 

[t3h_kyle]

I have the double critter nation cage with a lot of places to hide and sleep; with a lot of food and water sources too.

 

[t3h_kyle]

Mabel and Moxxie are closing in on 5 months! and Riley and riven are around 3 1/2 months old. They are pretty young so I know they have tons of energy, haha.

 

[jorats]

Oh...sounds like this could be play then. Usually females don't start bullying till they are a bit older. They are close in age, should be a good fit. I'd give them more time to fit in and settle down.