cross-species rodent cohabitation?

November 8, 2007 6:53 AM

Can a young male multi-mammate mouse live safely with a young male house mouse?

A few weeks ago, we found a baby house mouse on our doorstep, completely drenched and squealing loudly. We could not locate a nest, so we took him in and have cared for him since then. His eyes were open (seemingly only just) but he was not yet weaned, as the only thing he would accept for the first week or so was kitten-milk replacer. He has been very tame, seems to enjoy being handled and has never tried to bite. He is now weaned and is thriving. I estimate him to be about four weeks old.

My husband went out to get a larger cage for him and came back with a larger cage--and another critter. This new guy is a multi-mammate mouse. The pet store said he was a "baby," although he is already twice the size of our house mouse; I don't know his exact age. He also seems quite tame and allows us to pick him up without biting.

My husband's original intention was to have our two guys live together. We put them in the same cage for a while last night and they seemed to have no problems, although they didn't interact with each other very much. We did separate them before we went to bed, because I didn't want to leave them together without monitoring.

I'm wondering if anyone has tried cross-species cohabitation like this and if it works. From what I understand, both species are social and don't live as happily on their own, even with lots of human attention. However, I don't want our little guy to be bullied or harmed, and I'm a little more concerned because they are both males and I know males can be aggressive with their own species as cage-mates. However, since they're both young I thought it might still be a possibility. I read something this morning on multi-mammate mice and it said that they are "surprisingly tolerant of other species," so I'm hoping it may work out for the best. Any comments?

posted by dlugoczaj to Pets & Animals (13 answers total)

Most of the time, boys don't play nice with each other. That, and mice are fairly solitary. I would keep them separate.
posted by bolognius maximus at 7:06 AM on November 8, 2007

Well, as you noted, male critters don't tend to get along. That said, I have a pair of male rabbits that live together peacefully, so it can be done in some cases.

This faq says you have to introduce them at an early age and don't separate them again if you can avoid it. I think you could try it when you have plenty of time to observe. If they aren't going to get along it will be apparent pretty quickly - they will start fighting. Have a pair of leather gloves or oven mitts or whatever, so that you can reach in and separate them without being afraid of injury.

If you aren't aware, male mice can be incredibly smelly. Hopefully this won't be a problem for you!
posted by cabingirl at 7:10 AM on November 8, 2007

Oops, I missed the part where you already put them together (sorry). The faq I pointed to says you should try not to separate them for more than a few hours, so I guess if they get along you should leave them together.
posted by cabingirl at 7:12 AM on November 8, 2007

I'm guessing the bigger one will eat the smaller one, especially if he gets stressed in any way. Happens with gerbils and other small rodents all the time.
posted by Anonymous at 7:17 AM on November 8, 2007

To solve the mice eating mice problem, keep dogfood in the cage. Mice don't get enough protein from mousefood, so they eat each other. True story. I used to raise them to feed my lizard pinkies and sell the overage to the petstore.
posted by TomMelee at 8:33 AM on November 8, 2007

Speaking of male rabbits (cabingirl's comment). I spoke to a breeder recently who kept a pair of male rabbits together for years quite happily, and woke up one morning to find that one had torn the testicles off the other. I'd be wary of keeping small male mammals together.
posted by Leon at 8:54 AM on November 8, 2007 [1 favorite]

As they mature more, the larger mouse will engage in "lording" behavior (basically forced mounting) and may ultimately castrate the smaller mouse. Not a good idea to keep them together.
posted by OlderThanTOS at 9:06 AM on November 8, 2007

Please, please keep them separate. I once had two male white mice. I foolishly kept them together in the same cage and the bigger one murdered the littler one. I found him in a bloody white ball at the corner of the cage.

Nevertheless, it is very sweet of you to care for this orphaned mousie. I'm sure he will be quite happy in a tiny home of his own.
posted by Jess the Mess at 10:22 AM on November 8, 2007

Be prepared for a bit of heartache - mice don't really live very long and a 9 month lifespan wouldn't be out of the question.
posted by agregoli at 10:28 AM on November 8, 2007

Response by poster: Well, we prepared for heartache when we took in the little bugger in the first place--you can't really rescue a baby animal without accepting at least a 50-50 chance that it's going to die. I figure we've done pretty well keeping him alive and happy to this point, so no matter how long we have him we'll have done good.

And I think we'll do much better keeping them separately (this was my instinct in the first place; I just feel bad for my husband, who has now essentially paid a fine price for a second mouse rather than buying the cage we wanted for the first!). I appreciate the stories, ghastly as they are, and will be weighing them heavily in the balance.
posted by dlugoczaj at 11:42 AM on November 8, 2007

Sorry about the ghastliness...I probably should have left out that part.
posted by Jess the Mess at 1:45 PM on November 8, 2007

I've tried something similar with baby male hamsters. They ended up ganging up on the smallest one in the litter, and after that one was removed they ganged up on the next smallest one, etc...

I think there's a higher chance of getting small male rodents to live happily together if they were born in the same litter and are basically never separated. In your case, I don't think chances of success are very high. Though I totally understand the sentiment of wanting to see two rodents living happily together under one roof. It took many failed attempts on my part before I finally gave up on that notion.
posted by nihraguk at 9:36 PM on November 8, 2007

I've put mice from the same species together and one of them ATE the other. They had plenty of food, unstressed cage location, etc. I would not put them together. It's not worth the risk. They might get along for days (mine did) and then boom. It would be especially devastating since you hand-fed the little guy.

It sure sent me for a spin, and I haven't owned mice since. I still cringe when I think about it, and have fits of guilt and that was over ten years ago.
posted by tejolote at 10:48 AM on November 9, 2007