I see questions asked on various forums or groups about how best to make friends with mice. While there are several suggestions I can give you, the reality is that most of what determines a mouse’s temperament is genetics. A mouse with poor genetic temperament, that is inclined toward aggression or extreme fear, will never make a loving pet.
Breeders who work toward pet and show mice tend to also work toward friendly mice. It is both helpful to the breeder and to the new owner once a mouse is sold for the mice to be easy to handle and warm up to humans relatively quickly. While it’s also a benefit for breeders who primarily produce feeders, it is not as important and the amount of work put in is a lot more variable from breeder to breeder. It is absolutely possible to find sweet mice from feeder breeders as well as pet and show breeders.
Breeders working toward the goal
The primary way to achieve friendly mice is to choose bucks and does with the personality traits you are looking for and use those to produce the next generation. Depending on where you are starting from, this might be an easy process with all the mice being friendly enough to choose from, or it might take many generations and several years of work to go from flighty, bitey mice to ones that socialize well with people. In that case you would hold back the least bad, or the occasional decent ones to breed, and remove the rest from the breeding program with every litter or generation.
There is a lot of discussion about hand taming mice, and whether or not there is a long term benefit to socializing mice daily from when they are babies. From my experience and research, a lot of this depends on where you are in the process and how you go about doing it. As long as you handle each mouse about the same amount of time and same conditions as you go, you will still be able to see which mice tend to be more friendly vs. the ones that tend to be less friendly. If you favor the ones you find cutest, or if you try to work more with the ones that are less friendly in order to help them catch up to the others, you will likely end up with mice that are temporarily and artificially more friendly in your breeding program. You will not be choosing the best genetics for friendliness to pass on. These mice are less likely to improve your program and are more likely to revert back to more aggressive or flighty when stressors are introduced.
Handling the mice throughout can give a benefit if done correctly, however! The more comfortable your mice are with you handling them, the less stressed they will be when you interact with them while they are pregnant and nursing. Fewer stress hormones will be introduced to the litters, and the youngsters will see behavior modeling for positive interactions with people. The babies will grow up without negative connotations for humans. There won’t be any learned fear responses, so you will be able to assess genetic temperament more easily. Plus, they will already be used to interacting with you regularly and will transition to pet homes smoothly.
This sort of handling is not necessary, though. If the mice are still in the fear and aggression stage of the process, you will be causing more stress rather than less when interacting with them. It can make the process take longer than it would if you mostly left the mice alone to interact with each other. You can still assess during health checks and cage cleaning enough to see who you might want to hold back and that will provide plenty of interactions. If the mice are genetically friendly already, they will get used to being handled very quickly and can go from curious but shy to comfortable with you in just a few sessions of evaluation and play. From there you can get all the benefits of socialized mice for breeding and selling. As long as your mice have each other to interact with, they will have their social enrichment needs met without your contributions.
Pet owners bonding with their mouse friends
If you are a pet owner and want to have the best interactions with your mice, there are absolutely things you can do! Ideally you will be starting with genetically friendly mice, but these tips can be used for all mice. Each individual will have best results with their own combinations from the list, so if one thing doesn’t work there is still hope! This is also not going to be an exhaustive list of options for you to try. It is important to note that some mice will never be comfortable interacting with people. These mice should not be kept as pets because they will spend a majority of their lives in a fearful and stressed state.
One of the best ways to keep your mice happy, comfortable, and inclined toward the best temperament their genetics will allow for is to have them in a low stress environment for their habitat. That means make sure the space is not too large, there is plenty of clutter, and if you have does they have plenty of companions.
With genetically well tempered mice, you won’t have to do much more than just take them out a few times. These mice will still enjoy many of the suggestions I’m about to give and can become even more inclined to spend time with their people. Mice with poor genetic temperament will generally take a while to see improvements. It can be weeks or months of easing them into comfort.
When you first bring mice home, it’s a good idea to let them settle in for a couple days. If you get mice from a breeder, they can give you information on what is best for their specific lines, because some will take more time and some will take less. During the settling in process, you can start helping your mice get used to you by talking to them and spending time around them. They will become more and more used to your voice and movement patterns. You can also put your hand in their habitat and let them approach you to sniff and explore, or you can put in a slightly used sock or other small article of clothing. Both of these things will help them get used to your smell in a non threatening way.
When you have your hand in their cage, it often helps to coax mice to you by giving them treats (plain cheerios, black oil sunflower seeds, oats, and freeze dried mealworms are some favorites). If the mice don’t start approaching you fairly quickly, a low stress way of making friends is to drop a bit of food near your hand but far enough away that they don’t have to touch you. Soon your mice should have positive associations with your hand and they might start to climb onto you on their own. If not, you can try putting a treat in your hand again as encouragement.
When you get to the point where you are picking them up, either because they need to be moved for cage cleaning or when they are comfortable with you enough that you are moving to the next step, you have multiple options. Ideally, they will just climb on your hand, which is a fantastic display of trust and friendliness! Some mice will never get there, though, even if they are perfectly content once you have picked them up. Most people are inclined to try to scoop mice up with their hands, which works well if you can do it quickly. If you find they are moving away and you are following them, that can cause stress in your mice. It is too similar to being chased by a predator. Instead, you want to be brief in the process. You can coax them into a TP tube or an overturned hide and lift them that way. It allows them to have secure footing as they are lifted, and to have a bit of shelter during the transition. Another way to pick mice up safely is by tailing them. This is when you hold the mouse by the base of the tail near their body and lift them onto your hand or other surface. It causes no pain, but can cause some stress if they are held in the air for very long. It is less stressful, however, than chasing them to scoop them up.
Once you have your mouse outside of the habitat, you want to keep their experience positive. Keep your body calm and relaxed if possible. You can give treats here as well, or just let your new friend sit in your hand or run up and down your arm. Some mice like when you cup your hands to provide a cave like shelter. Others prefer to be allowed to move. You can let them walk from hand to hand a bit before putting them back in their habitat if they are trying to move away from you. If they seem inclined to jump from you, keep hold of the base of the tail. If they are showing these signs of stress, calmly put them back in their home and start the process of getting them comfortable again later. If your mouse chills in your hand, on your shoulder, or explores up and down your arms, they are likely comfortable enough that you can take them out regularly!
I hope this helps you find a wonderful bond with your mouse friends!