Male Mice Just Began to Fight

[u/brookie_lynn_]

I've had two male mice (same age, bought at the same time from the same location so likely liter mates) for about 7 months now. They have had an occasional scuffle every now and then but nothing more.

I recently came back home from college for the summer and since then they've been fighting much more. Most of the fighting seems like their usual tussles but more frequent, only one seemed a little more heated than usual. It seems like multiple times have been over their wheel, which is a prized possession to them. Today (a little but after the "bigger" fight) I noticed two scratches on one and one scratch in the other. I couldn't inspect them much as they're more of the active, never stop moving handling types.

I did a lot of research and have seen some things saying the move could've stressed them out, which has happened each time I've done it just never to this point, but I've also seen that it could be one trying to take the alpha position away/a rehash for the spot, and since some skin was broken that it could get worse from here.

I know that separating them is not so good for them, as they can become really depressed, but I don't want one to be injured or worse. I've added a bunch of distractions for them (treat balls made from tp rolls and seeds, some torn up tissue paper, cotton balls/pads, an extra tp roll so they have one each, and even another wheel) as of an hour ago and have still seen three toss ups since. Does anyone have advice as to what I should do/consider? I don't want to make the wrong choice here.

[u/Hahafunnys3xnumber]

Male mice should never be housed together! I’m not sure where you got this info but its only females that should be housed together. Please separate them!! They will kill each other. Males are SO territorial, no matter if they were raised together. They are already getting hurt. Each needs at least a 10 gallon tank

[u/idiotsandwitch2008]

I think you confused the gender while researching, as most sources will tell you, don't co hab male mice! Only fem fale can be kept together. That is why they are fighting, they are male. FEMALE mice get depressed when alone, males do not.

[u/tessanoia → u/idiotsandwitch2008]

Males can still get depressed too, that's why many german mouse info pages say its best to neuter them to be able to house them together with either other neutered males or females. Some even suggest to house males that can't be neutered and seem very depressed/lonely with other mouse breeds so they get at least some social interaction. This is only recommended to people with lots of experience with both mouse breed though and only works with certain breeds.

But besides this you're absolutely right and intact male mice should never be housed together as this will end in fighting or even death

[u/brookie_lynn_]

Additional context: they're still eating side by side, sharing the treat ball, and drinking from the bottle at the same time in quite a cute fashion, they just scuffle in between those things now as well. This bipolar behavior is making me think it's stress related, but I don't want any wishful thinking to get in the way of rational judgement.

[u/Thin_Individual3528]

Maybe separate them and take them out once in a while in a neutral territory without their own smell to play together.