Is one of my mice bullying the other?

[Peregrine]

Hello! This is my first real post after the introduction forum. Let me say that I've read many of the old posts on this board already, and everyone seems to be very helpful and knowledgeable. So maybe someone can help. One of my mice is very aggressive and comes right up to my hand when I put it in the aquarium. The other is very nervous and will hide until I put the lid back on. I've noticed sometimes that the nervous one will freeze and close his eyes when the bold mouse is going around. And just now, I saw the nervous mouse sniff the bold mouse, then suddenly the bold mouse aggressively started to groom (I think -- definitely not bite, though) the nervous mouse, and the nervous mouse froze and closed his eyes. It all looked very weird, and I'm concerned that the bold mouse is bullying the other one. If this wasn't bullying, can someone tell me what it was?

For background: I bought these two male mice a couple of weeks ago. I saw the first mouse, whom I named Paul, running around and playing in an aquarium filled with other mice at Petsmart. It was right next to the reptiles, so I knew they weren't really geared towards being pets. After watching him for a while, I thought that I couldn't leave the little guy there to a fate involving a snake or something, so I decided to buy him. The mouse book they had said mice get lonely on their own, so I picked another mouse in the same aquarium that I noticed Paul grooming and getting along with. I named that one Raul.

Anyway, first thing I did after setting them up in a 10 gallon aquarium with all the fixings was come to this board. Then I saw that you shouldn't get two male mice if they aren't from the same litter. These mice were in the same aquarium, but Paul is uniformly brown and Raul is black and white spotted. Most of the other mice in the aquarium with them were albino or brown and white spotted. The aquarium they share is 10 gallons and has a mouse-sized wheel, water bottle, ceramic food dish, wood house, and a paper towel roll and a toilet paper roll. Also, lots of bedding -- wood chips, but not cedar.

I thought I'd separate them if I noticed them fighting, but I haven't observed anything like that. Both of them have shiny, clean fur with no wounds anywhere. I had hamsters that fought as a kid (the pet store told us two male hamsters could share a cage -- yeah, right) and you could tell because they'd have little wounds they'd lick over and over again. The mice don't have anything like that.

I've started to get worried because Paul became so shy and Raul so bold. I don't want one to be tamer than the other -- I want to be able to pet them both!

Also, Paul and Raul sleep together most of the time in a nest inside a wooden box-house, though I have seen Paul sleeping in odd places lately, like the roof of the house (no bedding or anything up there, just bare wood) and the corner he likes to eat and pee in. And both of them used to run on the wheel side by side, but now the only time I notice the wheel is being used, Raul is the one using it. I'm not watching them 24/7, so I can't be sure that Paul doesn't use it sometimes. And Paul seems to be getting heavier.

Can anyone help? I hope I gave enough information. I also hope I didn't give too much! I really hope they can get along, because those two hamsters I had when I was little fought a lot. I didn't realize how serious it was until one day, one of the hammies had his eye bitten off by the other. That was awful. I separated them right away and things were much better. Actually, the one who lost an eye lived even longer than the one who bit it off! But I don't want to see these mice go through that. This is my first time owning mice, by the way.

I haven't had much luck taming them, incidentally, because when I put my hand in, Raul with nip my finger. Not hard, but enough to make me nervous. He goes straight for the finger! And Paul hides in a toilet paper tube as long as he can.

Thanks for any help or advice you can offer! And sorry that this is so long a post.

[Padfoot]

It sounds like a difficult situation, the problem is that it looks like bullying now, but things can get ugly really fast with mice, and you could come home one day to a dead mouse, even if things looked ok in the beggining. I would personally would be in the safe side, and keep them separated. However, I have a link for you where you can read some tips on how to keep male mice together: http://www.horns.freeserve.co.uk/mouse1.htm#males together? Good luck with your mice. 8)

[Peregrine]

Thanks for the advice! You were right.

So I made my mice a new multilevel home out of small boxes, and I put it in their aquarium this evening. I had read posts that said mice are less likely to fight if they have many little places to hide and call their own, so I thought this would work. I also zigzagged some thick rope around to provide more play space. Unfortunately, during the exploration phase, Paul and Raul kept doing that domination/grooming thing. One wouldn't stop following the other and they started fighting in a ball. I've never heard them squeak before!

I waited a little longer to see if it was a play fight. But soon they started up again with the following and the dominance grooming. They got into a chase/struggle that was definitely not play, and even when I knocked on the glass they didn't cease their fighting.

After I separated them I did some reading on the web and realized what I had done to escalate the situation. I put in a new house that was unmarked and this must have made them struggle for territory dominance. I feel like such an idiot! I thought I was making it better, not worse.

I was reluctant to separate them because I have read that they can never adjust after being separated for longer than an hour, but I was scared that the fighting would intensify. It seemed very stressful for both of them. I moved one of them to the cardboard box I let the mice play in whenever I cleaned their cage. I tried to move some of the familiar toys to the box and make a mix of new and old toys in both locations so that the mice wouldn't be freaked out.

The only problem is that I have only one water bottle right now. I can't get to the pet store right away (no car, no friends to drive me!) so I put some carrot in the aquarium to provide some moisture for the mouse who doesn't have the water bottle. Do you think this will be sufficient for his water needs until I can get a bottle?

I hope I didn't make the wrong choice in separating them. It just didn't look like play fighting to me, and I've been worrying about bullying for a little while now. I saw someone had posted that they realized after the fact that two of their mice had died from the stress of being bullied, so I didn't want that to happen to one of these guys.

Oh well. I'm going to get a second aquarium with its own water bottle and wheel the first chance I get. Any further advice anyone has to offer would be great.