I just introduced a new rat to my cage...help?

[Autumn]

I have a 3 or 4 month old "siamese" red-eyed rat, fairly large and very friendly.

Today, I introduced a smaller, younger, 10 or so week-old hooded black and white rat.
Both female.

My rat went over and started grooming the new one, then the new rat started making funny noise.
Like this: http://www.youtube.com/watch?v=te5eYP6dFzo
But in a deeper tone, I guess rats have voice differences hahah.

Then my older rat started grinding her teeth. Not bruxing, just chattering.

They were getting along fine until the younger rat came too close to the older, the oldder just pinned her and she squealed so I've separated them.

Is that sound normal?
And will these two get along?
How I can help them get along?

I cleaned the cage and the accessories and put the new rat in first. Then put my older girl in there. But I'm scared to put the older back in the cage now.
Please help.

 

[Merlyn]

The pinning is just a classic dominance action. When establishing who is the Alpha rat in the colony they will pin each other down. This doesnt hurt them, but the pinned rat will generally object to it by squeaking. You dont have to worry unless they start to bite and draw blood, otherwise let them sort their space out. Given a couple hours sniffing each other they will be best friends.

Aside from what you have already done, if youre really nervous about reintroducing them IN the cage try having them together in neutral territory, like on your lap where you can watch and be quick to act.

They will become friends in time... I have never had any problems with female introductions... even with age differences.. you just need to let them sort it out.

 

[★₤ɛasħa★]

You did not introduce them correctly. You can't just up and put them in a new cage together. They first need to be kept in separate cages set next to each other, so they can smell one another and get used to each other's scent. Do that for about a week and during that time, put them both on neutral territory (like a bathtub) and let them interact for a few minutes. Do this a couple times a day, increasing the time they spend together each time. The general rule of thumb is "No blood, no foul" but i separate mine when there is wrestling/biting accompanied by squeaking. After they've lived in separate cages and been introduced for a week, clean out one cage with bleach or a bathroom cleaner with bleach in it, to get rid of any scents. Then set up the cage and put them both in, watching them closely for awhile. If they fight, take them out and keep them in separate cages for another week with little meetings in between, then try again.

Unfortunately, some rats just don't get along and will need to be housed separately. But your best chance of having them live happily in the same cage is to CORRECTLY introduce them first. Good luck!

 

[CHARLES A]

the reason for the older rat to do this is because it is showing that this is its territory.