The Complete Guide to Pet Mice
Mice can make wonderful pets for most people. They are clean, friendly, fun and very active creatures who will give you hours of enjoyment and great company. They are also quite intelligent and, with lots of time and attention, can be taught how to do tricks and will develop strong personalities of their own.
- Mice are a great beginner pet for teens and adults.
- They are very active and fun to watch.
- They pose no threat of disease to humans.
- They are readily available all over the world.
- Mice are very sociable.
Mus Musculus Domesticus
Scientifically, pet mice are called Mus musculus domesticus, also known as "fancy mice". They are easily distinguished from wild mice due to their amazing variety of colours, shiny coats, longer bodies and varying eye colours. Fancy mice can be white, black, brown, brindle, spotted, grey, gold, roan, ginger or even multi-tonal, with black or pink eyes.
On average, pet mice can grow to be 5–7 inches long from head to tail and weigh very little at only around 1–2 oz.
The typical lifespan for a fancy mouse is 1–2 years, but some can live up to 3 years. Tumours are very common in mice, especially ones over 1 year of age.
Who are they suitable for?
Mice make excellent beginner pets for teenagers and adults. Due to their size, timid nature and extremely fragile bodies, they make very poor pets for children. Whilst mice are not aggressive, a frightened mouse may thrash, leap from your hands or bite you; they are able to draw blood. You should never pick up a mouse by the head or tip of the tail or pull them from cage bars if they are holding onto anything as you could pull the skin right off their frail, tiny bones. Mice can also very easily be injured, crushed or suffer from broken bones/traumas.
You do not need to have any experience owning pets to have a mouse as they are a great pet for responsibility, don't take up as much space as a hamster and can provide hours of fun company. Mice are suitable for people who are looking for a pet that is easy to care for, very active and will give them hours of joy.
Where can I get a mouse from?
You can get mice from lots of pet shops, especially very large ones or, more typically, from smaller chain stores. They are available all over the world.
Pet shops are the most obvious place to get mice from. Make sure you select one with a good reputation that has a lot of knowledge and that breeds its mice kindly without inbreeding or keeping them in cruelty. Always ask questions, and if something doesn't feel right, don't buy them. Often many pet shops sell sickly, inbred and overbred mice. Some are incorrectly sexed, have behavioural problems, are unwell or severely inbred, which can cause a lot of issues as time goes on.
Breeders are another option which may be able to provide you with specific types of mice, such as show-quality mice, certain colours, pairs or trios, specific genders, etc. through a range of prices. Typically the mice from professional breeders are not nearly as inbred, are good quality and come from healthy, lively parents that have been cared for very well. Make sure you find a good one, and don't be afraid to ask lots of questions. Good quality photos, updates, evidence of quality mouse care, breeding history and communication are essential. If a breeder is dismissive, doesn't ask you questions in return, won't provide photos or is selling them unusually cheap with little information, they are just rodent farmers, and the animals are likely sickly, inbred or poor quality.
Animal shelters are a good place to get mice; many have them looking for good new homes, and the mice there are in desperate need of a forever home. It's not very common you will have a mouse with serious health problems as only good-quality animals are suitable for rehoming in shelters, and the shelter will vet you out before handing them over anyway. Be warned that many of the mice in shelters could be anywhere from 2 to 12 months old or more and you are less likely to get a baby one.
Having something suitable to keep your mouse in is essential. They will spend most of their lives in their cage so be sure to get something that is within the RSPCA guidelines, is comfortable, secure and safe. Mice do not require as much space as hamsters but if you are keeping more than one you should greatly increase the amount of space you have for their comfort and to prevent a severe psychological disorder known as cage rage.
I will insert photos of perfectly suitable cages for mice to the right. Please avoid brands with lots of tubes, tight spaces or a low height. Many of these cages are far too small and well below the requirements set about by animal welfare. Plastic cages with lots of tubes promote negative bacteria to grow and fumes to build which can poison your pet or cause infections, the fumes can smell bad. These cages may look fun but they can be so physically harmful to your pet as well as not being spacious enough, it is important to give your pets the best possible chance to maximise happiness and lifespan.
Can mice have bar cages?
Absolutely. Mice can have most standard bar cages for hamsters, mice, etc. Fancy mice do not and cannot escape through 1cm bars unless they are extremely young and infantile. Whilst they do have few bones, if they cannot get their skull through the bars, they cannot get out and are not strong enough to bend non-flexi bars. Always select strong bars with a strong door. You can buy bar cages with very fine gaps if you are still worried. Typically, if you can't get an adult small-medium first finger knuckle through the bars, the mouse cannot get out.
Your other options are tanks or bin cages. If you choose a bin cage please do lots of research beforehand to prevent injury to yourself or the mouse. They can be hard to build, but very good and a much cheaper option. All should have a mesh or holed lid the mouse cannot escape from with plenty of air circulation, should be kept out of direct sunlight or from heat sources and should be clean and fully secure.
It is easier to handle a mouse than you might think. You can lift them easily by the root (closest part to the body) of the tail slipping a hand underneath to cup around them. Do not let go until they are calm and still to prevent them leaping from, or slipping through your hands. Mice do not usually bite but may do so if frightened and it is important to know if one were to bite you, you must not hit it, push it or let go of it as this will frighten the mouse further and make it harder to tame.
Always hold them over a soft surface, especially when taming, and keep them close to your body. It makes them feel safer. Mice can tame quite quickly within a couple of weeks and be very friendly pets. They enjoy human company and can be very easy to handle. After about 4 days, it is okay to start handling them each day for a few minutes. Let them get used to your smell, your face and your voice and they will warm to you quickly. Mice are very happy and curious and will soon eat from your hands and climb up your arm!
As I mentioned before, you should not attempt to pull a mouse off of cage bars or if they are holding something as it can pull the skin off of their bones or cause them serious distress and pain.
Can mice be kept together?
Absolutely! Fancy mice are extremely social animals, but only the females should be kept together. Females can happily live in pairs, trios, or even small groups with enough space and can bond very quickly. It is very easy to introduce female mice; seldom will they fight or not accept one another. Males, on the other hand, should be kept alone and away from other mice. They are insanely territorial and highly aggressive towards other males. Male and female mice can easily breed out of control and will likely fight. In some rare instances, males can be kept together if they have been brought up together from the same litter, but fighting may still occur. The moment blood is drawn, they should be separated for good.
Can male and female mice play together as long as I don't let them have babies?
Yes, they can, provided they are supervised at all times. Males and females may still fight; however, it is not a territorial attack, and males will not usually show aggression towards females and can be quite social with them.
Can two males play together if they are kept in separate cages?
No. You should not attempt to put two males together, especially if fighting has already occurred. This can be dangerous for you as well as them and may result in a very nasty bite to your fingers or the other mouse.
Can mice be kept alone?
Yes, but females may become lonely and depressed. Males will live very peacefully alone and often strike up a strong bond with their owners and do not require other mice to socialise with. Female mice are happier in groups with other girls and will happily compete in a non-aggressive manner for your attention.
My friend has a mouse. Can I let mine play with it?
Ideally, no. You don't know if that other mouse is carrying any infectious diseases or infections or what its temperament towards other mice is—regardless of gender. It is best to quarantine any mice before putting them together, especially if they have been near wild mice, other animals or unknown fancy mice. A mouse that appears healthy can carry a nasty illness that could make your little friend sick.
Like with any pet, mice can suffer from illness and injury. It is important to be very aware of this when getting a pet as it can be terribly upsetting if something should happen to them. Due to their short lifespan (1-2 years) this can be very distressing to some people.
Tumours: One of the most common problems in mice,especially over the age of one year. Mammary tumours are the most common, but both males and females can suffer. Tumours in mice need vet attention immediately and will require surgery to remove them which can in some cases cure it, however, they are most likely malignant and will return within a couple of months. Surgery can add time to their lifespan. Tumours can become terminal within 2-3 weeks and can appear very suddenly - even overnight! Benign tumours are not very common in mice. Tumours feel like peas or small balls that can be rolled around under the skin and do not have a root and cannot be drained of fluid.
URI (Upper Respiratory Infection): A serious infection of the lungs and airways which can become deadly in a matter of hours. These can be a very common problem for people who use pine, cedar or scented bedding. Small pieces of dust or chemicals can get into their system damaging the lungs. Dirty conditions can cause infection of the respiratory system. Older mice are also at risk. Symptoms include: sneezing, a "ticking" or "popping" sound, hunched posture, ruffled coat, sticky or closed eyes, gasping for breath, wheezing, tremors, leaking of fluids from the nose, mouth, etc. It can only be cured with antibiotics and the help of a vet.
Sticky eyes: Common in any animal, these can be caused most often by stress of allergies. Often people mistake red eye discharge for blood, it is actually just "stress fluid" leaking out and is especially common in mice and rats that have moved to a new home or have been through a rough time. You can gently bathe sticky or gooey eyes to keep them clear and the problem often resolves itself if there are no other symptoms such as breathing problems or a ruffled coat. If it worsens you should seek a vets help immediately.
Damaged Teeth: Mice tend to chew bars much less than hamsters and are less prone to a psychological condition called "cage rage" which causes a serious amount of mental and physical distress to animals. If your mouse is continuously biting the bars, they will damage their teeth. The good news is their teeth grow constantly and will likely grow back, however, they can be very damaged or even painful if they are severe. You may need to move your mice into a bin cage or tank and offer them wooden toys to keep their teeth down. If they have enough to chew on, they won't usually go for the bars.
Cage Rage: Less common in mice than hamsters or rats, but cage rage is a very serious mental condition causing a frenzied bar biting, possession towards cage or objects, difficulty handling, attacking cage mates, destroying their items and even making it difficult to feed/clean them out. It is caused by the cage being too small and can happen to 1 mouse alone or especially to a group. Mice need enough space to roam around, forage and climb as they are highly active and love to play. Bringing them out often and handling them is another great way to help prevent cage rage. It can be cured by moving them into a much larger space and keeping males separate.
Allergies: Mice are prone to allergies just the same as we are. They can be especially bad with sawdust, pine, cedar, chemical scents, certain cleaning products and dusty hay. It is always important to use animal friendly cage cleaners, buy quality wood shavings which are larger flakes with little-no dust and use appropriate bedding.
The pet shop sold me a pregnant mouse, what should I do? - Unfortunately there is not a lot you can do. You can keep the mouse comfortable and do plenty of research to allow her to have her litter in your home and when they are fully weaned and ready, separate the sexes and surrender them to a shelter (best option) or manually find suitable and good homes for them yourself (vet people thoroughly before handing them over). Your other option may be the pet shop will take the mice in once they are born as food, or they may sell them on. In some rarer cases they may accept an exchange for a different mouse. Whatever you choose to do, you NEED to make the pet shop aware of their error so they can prevent it happening in the future.
I was told my mice are both girls but I think one is a boy. What should I do? - Separate them immediately and contact the pet shop. They may not take a return or exchange on the unwanted male/female, but they should be aware. If you ask in the shop what gender they are and they sex them, make sure to look for a name tag and if the person does it incorrectly, report them. It is extremely unprofessional and against the code of conduct for most stores.
My mice are fighting, what should I do? If your mice are fighting aggressively or one is being confined to a certain area of the cage it is likely they are both males. Males are very territorial and highly aggressive towards other males. You should not attempt to ever keep them together. Sometimes on rare occasions females will fight. It is normal to hear some chasing, squeaking and see mounting even with female mice within the first week, this is a dominant behaviour and not a sign of aggression. If no blood is drawn and the mice are not getting hurt, just keep an eye on them.
Can I keep a mouse and a hamster together? - Absolutely not. You should not attempt to mix mice with hamsters, rats, etc as they will likely fight. Hamsters, especially females, can be extremely territorial and aggressive towards any other animals and will likely harm or kill them. Mice are best kept alone or with other mice.
I have a pet cat, is it okay to keep a mouse? - No. How would you like to live in a house with a lion and only a wooden door to separate you? you wouldn't. More often than not, rodents or small mammals are killed, seriously injured or sent into shock/heart attacks due to predatory animals in the house. It is cruel and very unfair on the mouse even if you shut the cat away they can still hear and smell it.
Can I keep a wild/garden mouse instead? - No this is cruel and unfair. Wild mice are not pets, they are more timid, typically have a shorter lifespan and can be crawling with harmful bacteria that could make you very sick. Please do not terrify a wild mouse to death by trapping it and trying to keep it. You do not know their age or whether they have babies that could be dying without their mother.
How much do they cost? - Mice can cost anywhere from £2-15 for around 1-5 mice depending where you buy them from, how they were bred, the colour rarity, etc. Most pet shops will offer 2 for £10 or something like that to help them be sold in pairs. Mice are quite cheap pets to purchase.
I think my mouse is sick, what should I do? Take them to the vets immediately. Mice can fall ill and die within hours and thankfully most ailments are treatable with antibiotics. Cysts or abscesses can be drained easily. Tumours can be removed in younger mice through surgery, however they often come back quickly and are malignant. The welfare of the animal is always the most important thing.
I can no longer care for my mouse. What do I do with him/her? - You should not get an animal without the intention of keeping it for its entire lifespan. Mice only live 1-2 years which is not a long time for us, if you cannot commit 1-2 years to a small animal you should not get any more pets. The best thing to do is surrender them to a shelter with all of their possessions so they can find a forever home.
Do mice carry disease? - Fancy mice and rats are the cleanest pets to own and carry no diseases transmittable to humans. They are not dangerous in any way, however, people with allergies to pets may have reactions to them if touching them. Mice kept as pets may pose a small risk of Salmonella if kept in poor environments due to poop, etc, and only if you touch them and not wash your hands afterwards.
Do I need vaccinations before I get mice? - As with any animal it is advised you are fully vaccinated before owning a pet as a precaution to you, but also to the animal. They do not have our massive immune systems and with improper hand washing or vaccinations you could easily kill your new pet without meaning to. You won't catch measles or anything from a mouse, but it is always better to be safe.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.