Keeping Mice Together & Introducing Them

by CallaLily Thu 07 Apr 2016, 8:52 pm

The content on this page was first published on The Fun Mouse website and has been reposted with permission. Please do not reproduce in any way.

Keeping Mice Together

Keeping Mice Together
Mice are known to be social creatures, however, natural instincts sometimes limit who can safely live together. For example, female mice usually love their female friends, but many owners discover that their male mouse doesn't appreciate having a male roommate. Read on to learn more!

Can female mice live together?

Yes! Female mice are companion animals and love to be housed with each other. A female should not be housed by herself unless there is an extreme circumstance such as fighting, which is very rare. It is rare for females to fight, as long as they have been introduced properly. If the mice have not grown up together, it is imperative that you introduce the females properly. You can find tips by visiting this link: https://www.petmousefanciers.com/t39-introducing-mice

Additionally, females should be housed in groups of 3 or more unless you have additional females in other colonies at home. There are two reasons for this: The first is that, if a female loses her only companion, she may get so lonely she actually dies of a broken heart (this isn't unheard of in humans either, such as one person losing their long time spouse). This generally happens within a week of the friend's passing. The remaining mouse will mope around, looking for her. Her diet might decrease and she may lose weight. Having more than one remaining allows them to comfort each other through their loss, helping them avoid depression. The second reason is that a third mouse can help make sure the relationships stay balanced. For example, two mice under a bossy alpha will help make sure that it doesn't get too intense for one, because there's two for the alpha to focus on.

Can male mice live together?

Pet shop males should never be housed together due to the extremely high risk of fighting. Males that have been in contact with a female have a smaller chance of being successfully housed together. Males compete for females and if they smell one (even in the next room or on your hands from the previous handling) they may get aggressive. Males from well-tracked, domesticated lines from *good* and educated breeders can sometimes be housed together. This is more common in Europe. The main reason for this is because mice in some countries have been domesticated longer than others. Evolution is a big factor in taking the "nature" out of the mouse. Selective breeding helps as well. Males in the US are not inferior to males in other countries. They have just had domestic mice longer, and in turn, the mice have become more domesticated.

Males in the US will generally fight to the death, even littermates. This can happen from 4 weeks of age and beyond. Many people have tried to house their bucks together and most of the time it has resulted in death or serious injury. Most times the death or injury happens without any warning whatsoever. The bucks will be perfectly fine with each other one day but the next day one or more are dead. It does happen that fast! Even with the closest supervision when housing males together is a huge risk. When there actually is a warning that fighting is occurring, taking out the alpha male isn't always going to improve the situation. Once fighting starts, it snowballs. Taking the alpha male out only opens up the alpha slot to another mouse in the pecking order. Without the alpha, another quickly takes his place and starts to fight with all the other bucks. It's a never-ending chain of events until all bucks are either separated or dead. This is only natural, as sad or inconvenient as it may be. Housing bucks alone is the safest way to do things. A solo male will be perfectly happy with toys and TLC from his caregiver. Solo males are also more affectionate as you are his only friend.

Is it possible to keep a male and a female together without having babies?

The ONLY safe way to house a buck and doe together is to have the buck neutered. If this is something you are considering, please read the section of this site that goes into more detail about neutering, here: https://www.petmousefanciers.com/t16-neutering-mice

Don't ever assume that your mice are too old to breed. Mice can produce babies their entire lives! It might take longer for the doe to get pregnant, but given time she will. Breeding too old can prove deadly to the mother and her litter. The risk is NOT worth the life of your mice! Additionally, if the buck is left with the doe after birth, she will likely get pregnant again directly after birth, resulting in back to back litters. Back to back litters will always result in babies less healthy than they could be, should they not have been doomed to a worn-out mother. The second litter resulting from a back to back litter will nearly always die before the first litter of babies, suffer more illness, and have a higher instance of tumors than the first litter. The mother will also suffer because of her large burden of all those babies taking so much from her. They will all suffer.

by AppleCheeks Sat 09 Apr 2016, 8:41 pm

Introducing Mice

This section was written to help you introduce female mice. We do not recommend introducing male mice as it usually always ends in disaster, as noted in the section above. Please visit these link for more information:
https://www.petmousefanciers.com/t142-males-living-together-warning-graphic-photos

Before you begin introducing mice to each other, it's important to observe proper quarantine. Read this link for more information on how and why: https://www.petmousefanciers.com/t7-quarantine

When introducing female mice, don't give up unless you have to. If they fight, separate them for at least 24 hours, if not a week, and try again. After living alone for a while they often learn that they really do want a roommate after all. Sometimes trying several times is what is needed. Keep in mind that not all introductions are going to be successful, but most are. Some mice are just not going to get along no matter what you do. Just like people, we all have people that we get along great with, and some that we just can't along with. Every mouse has its own personality and will clique better with different mice. If you get a really stubborn doe, try only introducing her to one other doe instead of a group. Mice often bond well with only one roommate. This might help. Later on, you might be able to add more mice to the group.

Fighting and Arguing

There is a big difference between fighting and arguing. All mice argue, even the best of friends. Sisters will argue with other sisters, mothers will argue with daughters. Arguing is nothing to worry about. You might argue too if you were locked in a room with the same person (or people) every day. Arguing may involve some mild nipping, squeaking (perhaps even loud squeaking), slapping, kicking, tail rattling, etc. However, arguing does NOT involve blood. At the first sign of blood, or you know blood is going to be drawn, separate them right away! Do not use your hands to intervene, use a TP roll or something that is gentle for them, yet saves you from being accidentally bit in the heat of their moment.

Neutral Territory

There are a variety of ways to introduce mice to each other. All options center on one very important thing: neutral territory. You don't have to go out and buy everything new, but you must scrub everything down really well. See this link for further instructions: https://www.petmousefanciers.com/t36-cleaning-odor-and-bedding

When setting up neutral territory, make sure everything is in a different order than how any of your mice have it in their tank already. It is also very important to supervise your mice for a long time after their initial introduction. Sometimes mice seem like they love each other and then a week later they start fighting. When introducing mice plan on spending a good majority of the day with them. You can even carry their tank around with you from room to room so you can still get things done but you are there in case you need to separate them quickly. If the mice do fight, always have a toilet paper roll nearby so you can use that to break them apart, rather than your hand. If you use your hand to separate them, expect to get bit! It's doubtful that they will intend to bite you, but if you get in between a fight, they may miss their target and get you instead.

Small Introductions

Sometimes smaller space is better when introducing mice. Mice should always have adequate space no matter what, but introducing them in just enough space to fill their needs can really help force the mice to share. Part of the problem with introducing in large areas is that the mice may stake a claim on something as "theirs." Then if another mouse comes into their claimed area, a fight will break out. Introducing mice in a smaller area will force them to share as it will be harder for anyone to stake a claim on anything. When introducing mice in a smaller area, make sure they have everything they need (water, food, housing, etc). Also, make sure it is neutral to everyone and large enough so they do have adequate space (do not cram mice into anything for any amount of time!). Once the girls are getting along well in the smaller space for about a week, a transition to a larger area will likely go smoother than if you just introduced them into the larger area to begin with. Remember, bigger is always better for females' permanent living.

Love Your Roommate

If you have two tanks of mice that you plan to introduce, you can place one tank inside the other, pending one tank can easily fit inside the other. You can NOT use this method with cages or anything with bars or mesh where the mice can fight through the bars. Remember, mice can fight through the smallest openings, grabbing tails, fur, etc. Make sure that the outside tank of mice can't get on top of the inside tank, as you don't want them to fight through the mesh lid. Let them live like that for a few days to a week. During those days, you can take a little bedding from each tank and place it into the other tank. This also helps them get to know each other's smells better. When doing this, the mice get used to living together without taking the risk of them actually being able to fight. When placing them together they might be so used to seeing and smelling each other that they may not argue much at all. When you introduce them in the same tank, make sure to introduce them in neutral territory. Be aware that fighting can always happen so you should always observe them together for a long time after the initial introduction.

Love Your Neighbor

If you are not able to or choose not to place one tank inside the other, another great option is placing two tanks next to each other and swap the mice from one tank to the other each day (i.e. remove mouse A from her tank, place mouse B in mouse A's tank, then place mouse A in mouse B's tank). This allows them to get used to the other one's smell without coming in direct contact with each other. After doing this for a few days to a week, introduce the mice in neutral territory. Be aware that fighting can always happen so you should always observe them together for a long time after the initial introduction.

Sweet Smells

Sometimes placing a small dab of vanilla on the rump of each mouse being introduced works wonders. When a drop of vanilla is placed on each of their rumps they all smell the same. Mice that smell the same often accept each other easier. Along with the smell, the vanilla also works as a distraction. The mice will be more concerned with cleaning it off than bullying each other. Vanilla either works right away or it doesn't. If the mice fight, the vanilla isn't going to make a difference later on. Introducing them and then placing vanilla on the rump isn't going to do any good. Vanilla only helps the initial introduction.

Playground Intros

You can set up a mouse playground in a bin, tank, bathtub, etc and introduce your mice there. Place many fun toys and things to climb on in there so it gives them a lot of distractions. They will usually be more concerned with their surroundings and not as concerned with each other. Let the mice play in the play area for a little while, giving them time to get acquainted. After the playtime, place them in a neutral tank and watch them for a long time in case fighting occurs.