You’ve got the basics covered. Your mice have a clean tank and bedding, fresh water daily, a high quality diet, a safe wheel, and a hide to sleep in. Their social needs are met, because you have at least three mice, and they get along nicely.
Here are four ways you can make their lives more interesting. (Read why you might want to do this.)
This is the easiest way to make life interesting for mice. Here are some of the biggest hits with my mice:
Sprouts. I bought a plain two-tiered seed sprouter at the grocery store — any sprouting kit will do. You can sprout any seeds that are safe for mice to eat. You don’t need to wait for a full shoot and root to form; a peeking little tip of a root is enough.
Sprouts are great because they contain micro-nutrients that dry pellets don’t have, and they contain a lot of water, which is good for digestion. And mice go NUTS for sprouts. I’ve successfully sprouted: wheat berries, spelt, kamut, millet, oats, barley, and brown rice.
Fresh veggies and fruit
Mice need some fresh foods in their diet. I've had most enthusiastic responses to cilantro, baby kale, wheatgrass, young parsley, raspberries, and blueberries. (Organic, because mice are very cancer-prone.) Rotate your veggies to keep them thrilled!
Treats (in moderation!)
Hide treats in different parts of their cage. Better yet, wrap the treats in paper first (phone book paper, brown paper, plain white printer paper), so they have to nibble through the paper to get to the treat.
Best healthy treats: Dry mealworms, plain unsweetened Cheerios, raw sunflower seeds in the shell (if your seed mix contains sunflower seeds, pick them out and offer them as treats), whole oats, and oatmeal flakes.
Mice also love eggs! I make my mice pancakes: I scramble an egg, mix with oatmeal (and veggies/flax seeds if in the mood), and fry it with nothing else on a pan. Wait until fully cooled, and serve. You can make a pancake out of anything listed above. Don’t add sugar— they will love it as it is! And of course, remove any uneaten foods that can spoil later that day.
This one is controversial, because soil can contain critters that can bother mice, which is why soil is not usually used by mouse keepers in the US. Do your research and make your own decision with this one. I first got the idea to use soil when looking at German mouse habitats, and decided to try it when I read about the effects of good soil bacteria on the mental health of mice (solving mazes more quickly, resistance to PTSD, depression, and anxiety, and persisting in swimming in water bins instead of giving up in experiments). I want happy mice! Plus, mice adore digging in soil, a natural behavior that comes pre-programmed in their little brains. I’ve been using soil for several years, and haven’t had a problem yet.
Use organic, indoor potting soil only, and replace it every week. Simply put soil in a box, mix in seeds, oatmeal, and treats into the soil, and watch your mice dig away! A digging box, like this one by #MumblebeesMouseHouse, will keep the soil more or less contained, and the mice will love being hidden "underground":
Soil has the added benefit of naturally eliminating odors.
3. Foraging Walls
Whether you have a small tank or a huge vivarium, a foraging wall will multiply the amount of usable space. A foraging wall is simply a piece of cardboard that perfectly fits your tank wall, with steps, passageways, and hides for your mouse to explore. Every morning and evening, I scatter treats in new locations on the foraging walls. The mice do their rounds, following their noses, and never know what they will find and where they will find it. This is a great way to add variety and excitement to their lives. I love the walls in Mumblebee’s shop, and incorporate them into my mouse house.
Foraging walls and other structures should be made of clean cardboard (with no labels, stickers, or paint), plain popsicle sticks, unbleached coffee filters, plain printer paper, phone book paper, brown paper, Elmer’s glue, and hot glue. I also incorporate small glass baby food and yogurt jars, being careful to glue them on very securely. All foraging items get thrown out after 1-4 weeks, depending on how dirty they get and how many mice you have.
4. Complex structures
Using the same materials as foraging walls, you can create complex, varied structures for agility and exploration. If your mice live in a small tank, and you simply don’t have the ability to give them more space (other than foraging walls), you can make a mouse playground for them: put down a felt blanket or brown paper on a table, and lay out your cardboard and popsicle creations on the table along with a wheel, food, and water. Scatter treats, and take your mice out for daily exercise early in the morning or late in the evening, when they are most active. When you’re done, put your mice back, and place the play items in a box. Always supervise!
Here are examples of complex structures for mice. Search the hashtag #mousetopia for ideas, and tag your own creations!