Mouse Care Guide
Mice Need Friends
Mice are social animals who live in large groups in the wild. It’s still an instinct in pet mice to prefer the company of other mice over a solitary lifestyle.
We recommend keeping a group of at least three mice. Start with two and add another mouse about six months later. You can then add a fourth mouse six months after that.
This way, you have what’s called a “rolling group” of mixed ages. This means no mouse will be alone if and when a companion passes away. Mixed-age groups of mice also get along better than same-age groups.
An exception to this rule is unneutered male mice, who should typically live alone. This is because they can show aggression towards other male mice, and housing them with female mice will result in babies.
There are primarily two ways to house male mice. If it is unneutered, house a male mouse alone. It’s preferable, however, to neuter your male mice and house him with a group of females.
There are exceptions where male mice may live together. You can also keep male mice with female soft-fur rats.
Mice need an enclosure that is secure and escape-proof, as well as simple to clean. It also needs to have adequate ventilation. There are many mouse cages available, but not all of them are really suitable for mice.
Types of mouse cages
You can keep mice in a tank-style enclosure with a mesh lid, or in a wire cage. The floor and any surfaces within the cage should be solid, rather than made of wire or mesh. Wire and mesh flooring can damage a mouse’s feet and legs.
Additionally, mice cannot use cages made of wood because their urine will damage the wood and cause a buildup of ammonia. Mice can also chew through a wooden enclosure and escape.
A mouse cage made of wire or mesh should have openings that are 1 cm or smaller. Mice can squeeze through openings larger than this and escape. The wire should also be strong enough to withstand occasional chewing.
Another option is a DIY bin cage or another type of DIY enclosure.
Minimum cage size for mice
The minimum cage size we recommend for mice is:
32 inches long by 19 inches wide and at least 15 inches high
This totals about 600 square inches of unbroken (levels do not count) floor space. A 20-gallon tank can be used for two mice in a pinch, but we recommend 40 gallons or larger.
In the UK, the minimum size requirements are as follows (we recommend following these in the US and elsewhere as much as possible, too):
Minimum height: 19.5 inches (50 cm)
Minimum floor space/footprint: 31.5 x 19.5 inches (80 x 50 cm); 614 square inches (4,000 cm squared) for two mice (we recommend adding at least 120 square inches for each additional mouse)
Many websites state that a 10-gallon tank is large enough for two or even three mice. However, almost all mouse owners would disagree that this is enough space for the mice and everything they require.
Filling the space
Keep in mind that the larger your mouse cage is, the more enrichment you’ll need to put inside it. Mice are afraid of open spaces, so any space in their enclosure should be filled with hideouts, tunnels, and toys.
Another factor to keep in mind is that, while tanks are popular enclosures for mice, very large tanks aren’t suitable. If you have a 20-gallon tank, airflow can effectively keep ammonia from settling in the bottom of the tank.
55-gallon or larger tanks are deeper, and they don’t allow for sufficient airflow. This means ammonia will sink to the bottom of the tank (it’s heavier than air), which can lead to serious health problems for your mice.
You can use three different types of bedding for your mice. Each type of bedding serves a specific purpose, which you can read all about here.
You do not need to use each of these types of bedding, and you can use a simple paper bedding for most of your mouse’s needs.
However, many owners find a benefit in using all three types, or at least two different types of bedding.
Here’s a brief overview of the different kinds of bedding mice need:
Mouse substrate should cover the whole bottom of the enclosure and ideally be six inches deep or more.
Many mouse owners choose a substrate made of aspen wood shavings, shredded paper, shredded cardboard, coco coir, and/or hemp fiber. There are also some other options for absorbent substrates.
Nesting is bedding that your mice will use to create cozy nests, both above ground and in their underground burrows.
Nesting materials include tea bag paper, shredded paper or cardboard, and hay.
Litter is a different type of bedding that you’ll use in the corners of your mouse cage, which is where mice typically prefer to pee and poop.
Litter should be made up of absorbent paper pellets. We don’t recommend using wood pellets, as they can break down into sawdust when they absorb moisture.
Food and Water
Mice need 24-hour access to fresh, clean water, either in a dish or in a rodent water bottle. We recommend using a water bottle because mice can quickly make a bowl of water dirty with bedding and droppings. Some mice will chew their water bottle, in which case you can use one made of glass.
Feeding your mice foods that are high in water content is not sufficient, and they need to be provided water at all times, too.
In terms of diet, mice eat a mix of pellets or mouse lab blocks and fresh fruits and vegetables.
We recommend scatter-feeding your mice, which means placing their food around the cage for them to search for and find.
Mice can be given dried mealworms, crickets, and other insects as a healthy treat.
It’s also important to know that mice eat their own droppings to help them absorb vital nutrients. If you notice your mouse eating its droppings, this is normal.
Mice are one of the small pets that require the most enrichment items in their enclosures.
Mice fear open spaces, so their whole cage or tank needs to be filled with not only bedding, but also hides, obstacles, and toys.
For this, you can use standing hides, tunnels, hanging ropes, hammocks, and anything else your mouse might find interesting to climb, burrow under, and explore.
Mice also enjoy using a wheel. You can choose a regular upright wheel or a flying saucer wheel, but we recommend providing both options. If you can only choose one, provide an upright wheel.
It should be at least 8 inches in diameter and made of solid material rather than metal bars or mesh.
Keeping your mouse enclosure clean is essential to maintaining your pets’ health. A dirty cage can quickly least to serious respiratory issues, as well as foot pad infections (bumblefoot).
You should spot-clean your mouse cage daily or every other day by removing soiled litter and bedding. Look and feel for bedding and litter that is moist or contains droppings, and take this out. Replace the amount you’ve taken out with new, clean bedding.
The frequency with which you clean the entire enclosure depends on the size of your cage or tank. The larger it is, the less frequently you’ll need to take the bedding out and completely clean the enclosure.
On average, you should plan to clean your mouse cage or tank about once every two weeks.
When you do completely clean out your mouse cage, mix in some of their old bedding with the new bedding. This helps decrease stress in your mice because they can recognize their own familiar smells.
Free Roam and Playtime
In addition to an enriching cage or tank environment, mice can also benefit from “free-roaming” or exploring a larger area.
This can be on something like a bed or table, or you can set up a playpen in your living room or pet room.
Many mouse owners also use their bathtubs as a play area for their mice. Just lay down some blankets, towels, or puppy pee pads, plus some tunnels and toys for your mice to play with and some snacks.
This provides a great environment for you to physically interact with your mice without having to grab them and hold them, which they may not enjoy.
Mice are self-cleaning creatures, and you rarely need to intervene as their owner. As long as you’re keeping your mice in a small group and their enclosure is clean, they’ll be able to groom themselves and each other very well.
Unlike gerbils and hamsters, mice do not need a sand bath to keep themselves groomed. In fact, their delicate respiratory systems often make it a better choice to avoid sand baths.
If you notice that your mouse’s coat is looking dirtier than normal, it may be time to take them to the vet, as this can be a sign of poor health.
If you notice that your mouse has something stuck on them and may need help cleaning it up, don’t get the entire mouse wet. Gently use a towel with warm water to spot-clean the area which needs to be cleaned.
Bonding and Interaction
Mice are prey animals, so they’re hard-wired to avoid being picked up and carried. For that reason, it’s important not to force interaction on your mice and slowly build trust with them, instead.
If you want to bond with your mice, start by letting them settle into their new home first and foremost. For the first week of owning your mice, you should speak softly and move slowly around them as much as possible and just help them understand that this is their home and it’s safe.
Next, you can start offering treats to your mice through the bars of their cage, and eventually in the palm of your hand. As your mice start to trust you more, they’ll start taking food out of your hand and even climb up on your hand.
If this happens, you can slowly lift your mouse a short distance and place them back down, which helps them get comfortable gradually with being picked up.
If you want to interact with your mice in a playpen or the bathtub and they’re not comfortable being picked up yet, you can urge them into a tunnel or hide and pick that up with them in it to transport them.
Never pick up your mouse by the tail, as this will set you back in the bonding process. In an emergency situation, you can pick up your mouse by the very base of the tail. However, this should only be used when there is no other choice, like if the mouse is in danger.
Mice Are Nocturnal
If you notice that you rarely see your mice during the day, don’t panic. This is completely normal as mice are nocturnal.
Mice are most active at night, so you should try to interact with them when it’s dark outside. You do not need to cover your mouse cage during the day or at night.
However, it may benefit your mice to avoid using lights after the sun goes down in the area where your mouse cage is. This will help signal to your mice that it’s nighttime and time to get up and get active.
If you find that your mice are mostly active when you’re asleep and you want to watch them at their most active, you can set up a night-vision camera in front of the cage to see what they’re doing all night!
Avoid waking up your mice during the day while they’re sleeping, as this can cause them significant stress.