How to Introduce Two Pet Mice to the Same Cage

Updated on July 25, 2015

Pet stores like to confuse mouse owners. Nearly every store I've visited has a little card or plaque that says, "Mice are social animals and get depressed without other mice." However, every time I've tried to buy two mice--especially male mice--the pet store worker will tell me, "If you get two, they'll fight." Advice like this makes it hard to make the right decision for your would-be pets.

While it seems contradictory, however, both of these statements are true. Mice will fight, but they like the company of other mice. They have instinctual issues to resolve--mostly male mice, and for the rest of the article I will discuss male mice unless otherwise noted--and that can lead to fighting and sometimes bloodshed. For more information about this, you can read my hub at http://jplaj.hubpages.com/hub/alphamouse, but I'm sure some of you need to integrate separate mice into the same cage. I can't provide an all-encompassing guide to do that, but I can relate what I did to integrate my mouse, Hannibal, with two new friends, Sasuke and Gaara.

The easiest way to keep multiple mice in one cage is to buy them young, preferably from the same litter, and buy them all together. Mice who live together as children--such as Sasuke and Gaara--tend to cohabitate as adults better than mice who don't know each other. Furthermore, we introduced two children to one adult, which initially gave Hannibal the edge in becoming the alpha mouse, which turned out to be a mistake. Mice fight for dominance and generally accept the chain of command once they establish it. When Sasuke grew up, though, he had a stronger alpha-mouse behavior, and challenging Hannibal for the position turned bloody.

Therefore, I recommend introducing mice before they've all matured, or after they've all grown completely. Introducing animals at mixed stages of development might not help in the long run.

Introduce mice in a box and they won't fight for territory
Introduce mice in a box and they won't fight for territory
Mice are social and enjoy doing things together
Mice are social and enjoy doing things together
Sometimes, even mice who live together peacefully will have conflicts
Sometimes, even mice who live together peacefully will have conflicts
What do you see: Two mice having fun by offsetting the weight of their wheel, or two mice fighting for control?
What do you see: Two mice having fun by offsetting the weight of their wheel, or two mice fighting for control?

But you may find that you can't do that. Pet stores usually sell children and adolescent mice exclusively. We could have waited until Gaara and Sasuke had matured, but we didn't quite have the experience to know better.

Either way, here are some techniques we tried, and I'll note how effective we suspect it was. To start, this is a list of things you need.

  • At least one cage for every mouse, even if you only have small travel cages
  • A box with very tall sides, preferably plastic but thick cardboard works too.
  • Fresh bedding
  • A few tubes and small boxes to give them personal space if they want it.

Introduce them on neutral ground

Mice claim territory. Throwing new mice into a pre-marked cage will start a fight. Instead, place them all together in a box. Mice jump and climb, especially young ones. Make sure the sides are about two feet tall and smooth. If the water bottle gets them high enough to jump out, stick it in a corner and put a sheet of cardboard over the top of that part of the box.

No one has marked the box. Without territory disputes, the mice probably will be more interested in each other.

Wipe their haunches with vanilla

Vanilla overpowers the individual scents of each mouse. If all the mice smell identical, we've been told, they will accept each other as friends.

We did this. It may have helped. It certainly didn't hurt. What we saw, though, was three mice spending twenty minutes wiping vanilla off their fur, then sniffing around each other. Each attempt we made to introduce them with vanilla failed. This is only one case, however, so I wouldn't rule out the option completely.

Wait until just before their bedtime

If you've had at least one mouse for any amount of time, you should know its sleep patterns. Most mice sleep during the day, so if you drop them in the box in the morning, they may be too tired to care about strange mice. But unlike the vanilla, this forces them to do something together. If they don't know each other (and even if they hate each other), mice will sleep together for warmth. Our mice seemed to bond over it.

Tolerate little squabbles

When you put them together, they will prioritize the establishment of a hierarchy. You will hear squeaking, and you'll probably see a good deal of male-on-male mounting. Just let it slide. The subordinate mice don't like it, but it doesn't hurt them and they need to resolve who's the king. (The alpha mouse seems to be responsible for grooming the others and for building the nest. Dominance doesn't indicate a tyrannical mouse.)

Pay close attention, though, to see that they're working out the pecking order and not fighting legitimately. Read this to help distinguish the two:http://jplaj.hubpages.com/hub/alphamouse

Be Patient and Persistent

We tried introducing these mice on three separate weekends. The first two failed miserably and we gave up. Hannibal went back to living alone and Gaara and Sasuke moved into the new cage together. After a few days, however, I noticed Gaara--a generally laid-back mouse--started picking on Sasuke. It annoyed me, but rather than split them up I wondered what introducing the more aggressive alpha male would do. For some reason, when I stuck them back in the box with Hannibal, they began to play nice with each other.

Give it Time

One source told us that if they didn't fight within the first hour, they probably wouldn't fight at all.

Not true.

Leave them in the box for at least 24 hours. Watch them closely--I had to keep the box by my bed. If they still seem cool with each other after a day or two, you can put them in a cage together.

Use boxes, cardboard tubes, and slats to create a changeable environment. Mice will more likely accept new friends if the cage feels different.
Use boxes, cardboard tubes, and slats to create a changeable environment. Mice will more likely accept new friends if the cage feels different.

Housing them Together

At this point, you should still have one cage for each mouse. If you own three or more, get at least two that connect. An average cage should house a maximum of two mice. So if you have a lot of mice, make sure a lot of cages can be strung together. Mice need space.

This part is tricky. You already had one mouse living in one of the cages. Before putting your new mice in with him, clean it thoroughly. You don't want any scent lingering to suggest anyone still owns the territory. If at all possible, though, change the layout of the cage. This will make the first mouse feel like he's moved into a new place, even if he remembers his home. If one cage is new--which at least one should be, since you need one cage for each mouse--put them in that one. They'll make their way to the other soon enough, but the more unfamiliar they are with the cage, the less likely they are to fight over it.

Don't Assume You're Done

Even if they accept each other now, they may find good reason to fight each other later. After all, we've all had bad roommates. I had one who piled trash in his room, never showered, stole from me, and ate my food. After he ate most of a cake I baked, I injected laxatives into the last piece and let him have it.

Mice don't often have access to laxatives, so they probably will just fight to the death.

Hannibal, Sasuke and Gaara lived together as friends for about two months with nothing more than a few minor squabbles. Then one day, Sasuke had had his fill of being dominated, fought back, and injured Hannibal pretty badly. They both survived, but we couldn't bring them anywhere near each other ever again. They had to live in separate cages and we couldn't take them out at the same time.

While this is our story, I can't claim that this will apply to any mouse you bring home. These animals resemble humans, and therefore have a complex psychology. Just use our experience as a guideline and be prepared for failure. If you have success, though, drop a comment and let me know what you did.

Edit: Know Your Alpha Mouse

Since writing this post, we've had a number of mice come and go, and I noticed an interesting trend among housing male mice together. As mentioned above, the three mice in the picture lived in relative harmony until Sasuke grew into adulthood and became the alpha mouse of the group. We had to separate him. Sasuke went to live on his own, while Hannibal and Gaara lived the rest of their lives together with not even the smallest squabble.

When Hannibal and Gaara died, we bought two female mice to replace them, and since one of them turned out to be pregnant, we ended up with three more mice. We let Sasuke stay in a cage on his own, while the girls got one cage and the boys, Sean Bean and Jon Snow, lived together.

The two brothers lived together with a reasonable amount of discord--as you'd expect among siblings--but interacted very well most of the time. Then when Sasuke passed away, things started changing. Sean Bean became more aggressive and territorial. When the fights got worse and Sean Bean terrified Jon Snow into spending all his time in a small corner of the cage--away from the food and water--we separated them.

Test this at your own risk, and always keep a close watch over male mice living together, but I suspect male mice can live together peacefully as long as the alpha of the group is separated, but living nearby. Sasuke's death, even though they never interacted, left the room without the scent (or so I assume) of an alpha mouse, and one of the others had to take that place. Leave a comment if you try this; I want to know if it works for other people.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      Jean 

      4 weeks ago

      I saved a tiny field mouse last Thanksgiving from a glue trap. I named him King Arthur. I kept him all winter and released him the following June in our yard. I had my carpenter build him a double walled plywood insulated house to live outside He was outside from June to October until it got cold. I had hoped he would have moved on but instead he moved closer to my house and held up in a crack in our cement near the garage. It got very cold and one night I set a have a heart and re-trapped him. He is inside in a terrarium.He is very lonely and waits for my company. Tonight I set a trap in my basement because I thought there was a mouse in our house and I was right. I trapped a mouse. After reading your story about introducing mice I would be very fearful to introduce these two strangers to each other. For now I'll wait for a warm day if we get one and release this mouse. If no warm days I'll keep him all winter and release him in the spring. I feel bad for King Arthur being so alone is there anything else I can do to make him feel less lonely. Thanks

    • profile image

      David Eustache 

      4 months ago

      It didn't work for us. My favorite male Mouse was killed and he was the alpha. The other male mouse was half his age and we raised him from birth. I am very saddened.

    • profile image

      juseleienez 

      5 months ago

      I love how they’re named after Naruto characters

    • profile image

      Mysterious stranger 

      7 months ago

      Probably something like nutmeg or cinnamon

      Responding to Olivia

    • profile image

      Olivia 

      10 months ago

      Could you use anything other than vanilla?

    • profile image

      Mouse owner 

      12 months ago

      Cassie, I would try another baby mouse but make sure it is close to same age and it is same sex. I would do the box method with them and let them mingle then place them together in the cage but make sure you clean the cage before you place the new mouse in it.

    • profile image

      cassie 

      13 months ago

      i recently bought two baby mice, and i already own two older mice, all females, i was prepared to have the older mice and younger mice in separate cages, and i was right to do so as i attempted to integrate them and one of the older mice drew blood. however one of the baby mice has gotten out of its cage, was not as well handled as the breeder led me to believe and managed to jump out of the tank while i was changing food. Now heres my issue, i am unsure the likelihood of finding the other baby mouse, sad as it is, though i will keep an eye out, the problem is my other baby mouse is now on her lonesome, she is only a little over 6 weeks old and seems very timid, so im wondering if i should purchase a new baby mouse for company for her as she is still young, and any other baby i would buy would be young as well. Would this be advisable ?

    • profile image

      Peachy_Mouse 

      16 months ago

      Have two males I recently bought as a sibling hopper pair of mice, one came from the pet store ill with a URI and I suspect that because of this his brother views him as the weaker of the two so of no real threat to his space and for the most part they live in harmony not looking forward to any fights but if anything serious dose happen they will be separated immediately.

    • profile image

      Experienced mouse owner 

      20 months ago

      Most female mice will like each other if introduced properly, it's very rare for female mice to try to murder each other.For males is it is the opposite of females, but sometimes males may be able to live with each other, I you see blood or blood drawn immediately remove them.

    • profile image

      Vanessa 

      22 months ago

      Miss lol, I'm pretty sure adult males are happy on their own. Getting another male mouse can lead to them fighting to their death and finding one dead is often the first sign of an issue between them that the owner sees.

      I wouldn't buy another male mouse to accompany yours, if I were you. I would try and spend time with your mouse to get it to view you as a companion.

      I'm not an experienced mouse-owner, though

    • profile image

      Miss lol 

      23 months ago

      I got a mouse named harry he is gray I think he is lonely so I was thinking to get another male mouse but I'm afraid they will fight what do I do if they fight I'm super scared so if anyone has any tips I'm all ears

    • profile image

      Ckkprincess 

      23 months ago

      What kind of vanilla do you put on the mice?

    • profile image

      MouserMom 

      4 years ago

      Growing up we had three mice in a cage at a time but they were all female and I assume litter mates as Santa had brought them all from the same shop. We joked that they had sleep overs. Each mouse had its own cage in each of the three kids' rooms and we ended up alternating which cage they stayed in each week. Your boys are super cute! My current two mice are girls and will fight over whose turn it is on the wheel every so often... At 2 am :(

    • profile image

      dbbbbbbbbbbbbbbbffv 

      6 years ago

      cool

    • holdenh13 profile image

      holdenh13 

      7 years ago from Louisiana

      lol i used to work at a pet store and i can't tell you how many dead small animals i had to throw away. the hamsters are the worst!

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, pethelpful.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://pethelpful.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)