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Mice/fighting at introduction between mice


QUESTION: Hi Natasha,

I have two female mice, Amy and Rory. Amy is the dominant. I often hear them playing and squeaking in the cage, and sometimes I feel like Rory may be getting hurt by Amy but there haven't been any signs of it until now. Late last night I heard them and I thought they were playing like usual, but I woke up this morning and Rory's ear is all bloody. The fur beneath the ear has been scratched away.

I'm wondering, do you think Amy but Rory and she is scratching at it, or is it mites? I watched her for over an hour this morning and she didn't scratch at it once, but when I came out of the shower, there was fresh blood and she was scratching it.

I separated them and deep cleaned their cage. I put Amy back in the original cage and Rory in a second cage. I can't touch bleach (allergic) so I used simple green cleaner.

I want to go to the pet store before work today and pick up some mite spray, but here's the kicker... I saw your instructions for another girl (her name was also Sarah, ironically), and in them you said to handle the mice. I have only had them since September and they will not let me touch them, let alone hold them. I can't pick her up and clean her ear, and if I spray her I can't take her out of the cage really to do so. I'd have to just spray her in place.

What do I do? I think she has mites but it could just be that her ear itches from an injury caused by Amy. In an odd note, when I tried to get Amy out this morning she almost bit me. Which has never happened. Normally they sniff my fingers or hand and then run away. On the other hand, Rory let me pet her once she was in the new cage alone. Do you think Amy was that dominant than she scared Rory so much she wouldn't let me touch her? She seemed to like the attention now that she was alone. I put the wheel in Rory's cage and for the first time in months she's actually using it, also. Amy would kick her out of it and it sat unused for several weeks. But she's active and happy now.

Any help is appreciated, I don't have much money and I can't really go to the vet.

Thank you :)

ANSWER: Dear Sarah,

First off, you have to keep these gals separated. The four reasons to separate mice are

1. The fighting never stops
2. There is blood
3. Someone is blocked from nest, food, water, or wheel, or
4. Someone is depressed, lethargic

It sounds to me like although we don't know about 2; 3 and 4 were true. Poor Rory was pretty unhappy.

Of course, since a mouse shouldn't live alone, they each need a cage mate. You should get little babies. If it turns out that Amy can't even get along with a baby, then you will have three in one cage and Amy alone- with the cages close so they can talk. I know they do, because when I had exactly that setup, when the single mouse died, the other three all got depressed and lost weight. Even though she had been aggressive with them, they were good friends in separate cages.

Because it is so difficult to use the spray, try waiting a couple of days to see if she stops making it worse. And watch both carefully for signs of scratching. At the same time, do your very very best to get ahold of some Revolution (selamectin). That is what vets (in the US..) use to treat any animal for parasites, though a vet might not know you can use it for a mouse. Here you can sometimes get a vet to sell you a kitten dose without a visit. Other than that, you can find a friend who has a cat or puppy (not a dog) who has some or can get you some. You must use the kitten/cat/puppy dose, not the dog dose, which is too strong.

Hopefully it seems like the problem clears up on its own. If you do have to treat them (they will both be infested), it will be a two person job, maybe even with gloves. The trick to holding a mouse is having her on one palm and holding the very base of her tail by her rump gently but firmly with your thumb and forefinger in the other hand. You can't spray her in place, because even if it were effective enough (probably not), it would be terribly hard to avoid her eyes.

In the meantime... You have had them since September and you can't hold them yet!  That is 6 months ago. Mice only live about 18 months, so it is about time to make friends. The following post includes a list of baby steps to make friends with a mouse. You may be able to go through them quickly. If you get new mice, they will learn more easily and the older mice will learn some from them.

Let me know how Rory looks in a couple of days. Hopefully mite treatment won't be necessary.



---------- FOLLOW-UP ----------

QUESTION: Hi Natasha!

Thanks so much for your advice. I have kept them separated the past few days, and Rory is LOVING it. She is more active than ever, bouncing around her new cage all the time, I hear her on the wheel, she's eating a lot, she just seems so happy!

Sadly, Amy is not happy. She hides in her little den and does not come out. I didn't have a wheel to put in her cage for yesterday, but today I reattached the old wheel I had (for now... it's a critter trail wheel and it sprays poop everywhere but I felt bad leaving her with no wheel since I can't get to a pet store right away).

I am going to go buy her a mate as soon as I can, I know she is depressed. I was just afraid that if it turned out to be mites, that I would end up having to treat 4 mice instead of 2. I have their cages right next to each other, they literally can see each other, but I don't think Amy can hear Rory. Rory is in a tank and Amy is in an open wire cage.

I looked over your instructions and I got Rory to come to my hand. I always thought it was strange that she wouldn't come to me. I had mice all through high school and they loved sitting in my pocket or playing next to me, or running all over me. They never cowered away from me. Rory was definitely being stifled by Amy. In fact, I made you a video! The link is here:

It's a little long, but I tried to show you Rory's ear. It looks better today. I got home from work and it looked like it had started healing, rather than getting worse. She is still scratching at it, though. It's in the video. I also caught her biting her fur on her side, but I honestly think I am overreacting because I am hyper aware to all her movements now. Amy is showing no signs of mites or scratching. She just sits there and sleeps in her cage and doesn't move unless I open the door. I saw her eating on Sunday, though, so I know she's at least eating. When I put the old wheel back on her cage she roamed around for a bit and then went back to bed (she is not the best with remembering how to get into the old wheel... it took her two days to figure out how to use it last time). Amy was climbing all over the cage the other night when I was home, so it's possible she's fine and I'm just overreacting. Even when the two of them were together they would sleep all the time and not come out, unless it was at night then I could hear them squeaking loudly.

Tomorrow on my way home from work I plan on getting her another silent spinner to replace the one I took out of the cage, if anything just so she doesn't send poop flying everywhere when she does figure out how to use the critter trail wheel again.

Do you think the mite scare is over? I picked up a bottle of the bird mite spray just in case. I couldn't find the mice version, but I read on here somewhere that the bird spray is the same thing, just less potent.

She appears to be getting better, but I wanted to give you the video so you could see for yourself.

The black fabric in there is an old t-shirt. When I was reading your steps you wrote about putting a baby in your t-shirt to smell you, so I thought I could do the same thing with Rory but instead of bringing her to the shirt I thought I'd bring the shirt to her. She loved it. I sat there for about 20 minutes before I put the shirt in and she came to me, but once I put the shirt in and let her run around and play in it awhile, she started running over to my hand and jumping on it. :)

If you want to see her ear on the first day it happened here's a short video for that:

Thanks for all your help :)

ANSWER: Dear Sarah,

I'm glad Rory is happy. Amy needs a friend right away. In fact, being alone and depressed can CAUSE mites to become a problem! So you don't want that to happen. I think the mite scare is over. Go getcha a couple of babies!

Of course they are sleepy in the day and awake at night... They are nocturnal :)

The bird spray is half as strong as the rodent one, but is often plenty effective for a mouse. The rodent spray is "flea and tick" spray; it is not labeled for mites.

Sounds great about the T shirt. She learned that your smell is not scary. That was fast!

I haven't watched the videos because I am on an iPad, but I will. If anything occurs to me when I do, I will amend this answer and you will be notified.

Squeaks n giggles,


---------- FOLLOW-UP ----------

QUESTION: I bought them both mates, and I'm trying to introduce them but they keep fighting! I put the very smallest of two in Amy's cage, and the slightly bigger one in Rory's. Rory and Amy are having none of it. I introduced them in a shared environment. While Rory and her new mate were meeting I cleaned her cage and put them back in it with new bedding and the bedding from their meeting area.

Rory is still fighting with her new mate.

Amy and her new mate just got put into their neutral zone, but they're fighting too! This is breaking my heart :(

Dear Sarah,

Chasing and squeaking, even for a couple of weeks, is completely normal. Remember what I wrote before:

The four reasons to separate mice are

1. The chasing and squeaking is nonstop
2. There is blood <--- is there?
3. Someone is blocked from nest, food, water, or wheel, or
4. Someone is depressed, lethargic

If none of these are true, no problem. Seriously! Squeak screech squeak screech! No one is getting hurt. It is communication. They have to figure out who is boss, even though it should be obvious by their size! If the baby is a little one, you may see her turn around to face the bigger mouse and stand up. That is a good sign. She is throwing herself on the adult's mercy, and the adult should respect that.

You can give the chased  mouse a break sometimes by picking up one of the mice. You can try blowing on them too. But in the end, they have to figure it out.

Let me know :)




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I can answer questions about raising mice and caring for them as pets, with knowledge from my 38 years of having fancy mice as pets. I have NO MEDICAL TRAINING and you should take a sick mouse to the vet; but if you simply can't, I will try to help you. I LOVE PHOTOS!!! I ALSO LOVE UPDATES! Let me know how the little tyke is doing later on, for better or worse, especially orphans. It also helps me to help the next person. Please first search first: use 'Natasha Mice Mouse' with whatever else your question includes. Or check out these links: **** YOUR FIRST MOUSE (my video; rough draft): **** TEN VIDEOS ON RAISING ORPHANS: **** SEXING MICE: **** And some GREAT MOUSE INFO SITES:


I have had mice for 40 years (since I was 5!). I raised them when I was a child but now I keep all females, and never fewer than three so that if one dies the others are not devastated, because they have each other.

I run Rats and Mice are Awesome on Facebook. The official name is Rats are Awesome.

B.A., M.A., M.A. in Linguistics: Yale University and University of Connecticut

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