Items you will need
A large aquarium, 10 or 20 gallon size.
Wood shavings to use as bedding
Mouse food and treats
Water jug with dropper tube
Make certain that your new pet mouse has all the fresh drinking water it needs, clean bedding and a means of exercise.
Do not attempt to keep a fully grown wild mouse as a pet. They can and will bite if provoked and wild mice can carry a lot of diseases, so be cautious and understand that full grown wild mice do not make great pets.
Wild mice can be kept as pets, same as any tame mouse you buy in a pet store, the only difference is, that wild mice have to be captured at one particular point in their lives, and not earlier or later. Plus, they live longer than the pet store variety of mouse and are generally healthier and stronger.
How to Keep a Wild Mouse as a Pet
In order to keep a wild mouse as a pet it has to be captured at an early age, but not too early. If you find a baby mouse that is still pink and hairless, that is too soon to keep it as a pet. These mice are still dependent on their mothers for nourishment. But just a few days later, the mouse will have it's fur though it's eyes will still be closed. This is the perfect time to capture the baby mouse because in a couple days when its eyes open, it will see you and it will bond with you, first through scent and then later, by sight identification.
When the mouse opens its eyes it will accept its human owners as family and will behave like a tame mouse. This is why it is crucial to get the mouse before its eyes are open. It will bond with you and allow you to hold it, and feed it by hand. Otherwise it would be afraid of you and would be skittish and confused when held by a human. A mouse this size can be fed through an ordinary eye dropper with a solution comprised of milk and melted cheese.
Keep the young mouse in a container big enough for it to rest comfortably and perhaps run around a little bit. Give it food and water. Peanut butter is an excellent choice as mice seem to go for it. They also love chocolate and cheese but will eat just about anything you give them, including meat. Mice in the wild will even turn cannibalistic at times when there is a food shortage, so meat is definitely not beyond them. You will probably need a large aquarium so your mouse can have a comfortable space to move around in, and an exercise wheel as well. Give your mouse some wood shavings for bedding and some sticks to chew on as rodent teeth grow continuously.
Wild mice live to be about three years old. Sometimes the domesticated versions live shorter lifespans of perhaps a year or a year and a half, but for the most part that is due to the fact that they have been interbred through so many generations that some of their DNA is altered from its original form. This is not to say however, that domesticated mice cannot live the standard three years but they are usually less likely to.
Most mouse owners try to keep only females together as a general rule. The males must be kept apart as they will fight if placed together and a male and female pair will overwhelm you with pet mice, so, since mice are social creatures, you should consider getting two females and keeping them together in one container. Change the bedding in the mouse's home often, because mouse urine is a scent you really don't want to have as the prevailing atmosphere in your home.