Bonding mice:

Ideally all mice live with friends. If you have female mice or a neutered male (intact males should not be housed with other mice) you can and should have them live in a group. They are social animals who do best in communal living.

Thankfully mice are often easy to bond. Here are our suggestions on bonding mice.

Start with a neutral territory. We suggest a carrier or small cage. You will want to make sure that this space is cleaned throughly and doesn’t have the scent of either group of mice. Add fresh bedding with no toys, hides or enrichment. You will want to provide ample amounts of food and access to water. Place all of the mice in the carrier and watch closely for any signs of aggressions. If there is any biting/blood drawn or excessive chasing remove the mice and try again later. Your mice will likely sniff each others faces and bottoms and may even squeak or kicking if one mouse is being a little bit too pushy. These are normal behaviors.

Once your mice have gotten over the initial introduction they will eventually settle down and hopefully lay together. You may notice that the new mouse/mice lay separate from the others, this is okay. Leave them in this space for 12-24 hours.

If your mice are sleeping together, eating together, grooming each other and there are minimal disputes it is likely safe to move onto the next stage.

Depending on the amount of mice and size of your initial introduction cage you will want to either move up a size (a 10 gallon is what we typically use as the second step) or start adding new elements. If you are moving up a size we suggest you follow the same procedure already laid out but carry over some of the bedding from the first enclosure to the second. If you have enough space to add enrichment consider adding a few toys. If your mice do not fight or argue over the toys for a few hours you can continue by adding a hide that has multiple exits. A bendy bridge is often a good option.

If all goes well (minimal disputes, sleeping together, eating together and grooming themselves and one another), gradually continue to add things into their space avoiding items where one mouse may trap another and continue to provide ample amounts of food and access to water.

Leave your mice in this space for 2-5 days while gradually filling up the enclosure with hides, enrichment, hammocks, ect.. After that you can clean out their permanent enclosure and follow the same steps over the course of a week or two until they are settled in together with a fully enriched environment.

Tips:

If there is any blood shed remove the mice and try again at another time.

If the mice are fighting over an item remove the item and give it more time or add a different item.

Humping is a normal way for them to establish dominance. If it is excessive you can separate and try again at another time but it is typically not a concern.

Take things slow and don’t be afraid to back track.

Introductions can be a long process or a short process depending on the mice. This is often a stressful time for both the care takers and the mice but a few days/weeks of stress will lead to a life time of kinship that will improve your littles life significantly.