Mouse Care Guide

Mice are small rodents who actually make wonderful pets.

They are very similar to hamsters, guinea pigs and other small animals in what they need and their behaviour, but do need a slightly different, sensitive care plan due to their sensitivity to light and noise. They’re also very quick to move and need to be handled carefully to avoid injury.

Mostly active at night, they thrive on the company from other mice – but can also great company for humans.

The first written reference to mice kept as pets occurred in the 1100 B.C. version of the oldest extant Chinese dictionary, so pet mice are hardly a new phenomenon.

But despite this long-term relationship, they can still be difficult to properly look after. The below guide is a good place to start to avoid running into any difficulties.

FACTFILE

  • Lifespan: 3 Years
  • Average Length: 2-3cm
  • Average Weight: 29–44g
  • Popular Breeds: Agouti, Self, Tan, Pointed, Patchwork, Marked
  • Diet: Opportunistic Omnivores. Rodent mix, vegetables, fruit, pulses, occasional insects
  • Origin: Asia

IMPORTANT THINGS YOU NEED TO KNOW

  • Most vets will likely accept mice but double-check first
  • Cost of care is relatively low, but it is worth spending that bit more for quality
  • Living in pairs is the best arrangement. Two females will be easiest, but two males should only be together if they were original littermates or they will fight
  • Any more than two mice will need a much larger cage
  • A male and female together will mate, and they can’t be neutered. They could produce litters every 4 weeks
  • Mostly nocturnal. They can be picked up and taught to be tame and friendly, but you must be gentle and give it time
  • Fancy mice all belong to one species – Mus musculus. But breeding for 200 years as pets mean there are now different colour species

WHERE TO BUY A MOUSE

We would always recommend contacting local animal rehousing charities as the first port of call. The RSPCA often has mice available to rehome, as will similar charities. Pet shops such as Pets At Home may also have mice for sale.

If you opt to buy them from a breeder, there are a few different things to think about. Babies should not be taken from their mothers until they are five weeks old and breeders should separate male and female mice babies at a young age.

It is best to take at least two mice from the same litter so they don’t fight with each other, and always ensure they have a fellow mouse to live with – don’t buy from a breeder who is trying to sell just one on their own, or will allow you to take a male and female together.

Checking how mice have been born and spent their first few weeks can be a big indicator of their health

Always check where your mouse has been bred to ensure mum and dad are healthy, and the mice have been given enough room to live.

Females reach sexual maturity at five weeks and can give birth every 3-4 weeks. They average eight to ten babies per birth and females can become pregnant within 24 hours of giving birth, so you need to ensure that the breeder is not dangerously overrun with mice where health could be compromised.

CHOOSING YOUR MOUSE

Health

Pet mice should be alert, receptive and look healthy. They will have bright eyes and clean ears, eyes and nose. Weight is a very important thing here – check it is a healthy weight for the size of the mouse, as weight loss is often the first sign of illness

Age

Pet mice must be over the age of 5 weeks before they can be separated from their mother. Mice only reach their full size at 3 months, so be aware your mouse may still be growing. They live for an average of 1.5 to 3 years, so be aware of this

There is no way to predict how long a mouse will live for, but a reputable breeder will be able to tell you how old they are at the time of purchase

Sex

Two females from the same litter together are the best arrangement. This way, you don’t have to worry about breeding, and they generally shouldn’t fight with each other.

But two males can be aggressive with each other. They also have a stronger smell because their urine contains a musk-like substance, so females are the better pet

Handling

Mice are usually friendly and easy to handle, although those which are timid could bite if they aren’t used to being handled.

They can be taught to be handled with the help of food and Classical Conditioning. To pick up a mouse, hold the base of its tail gently but firmly, then lift the back end gently and slide your hand under the mouse’s body

ENVIRONMENT

Housing

The best home for your pet mice is either a wire cage with a plastic tray floor (one for a hamster is a good bet) or a tank (glass or plastic) with a secure wire lid. Don’t go for wood as it will become smelly and is hard to clean. The wires must also be suitable for mice, with smaller gaps the width of your little finger that they can still climb on.

Mice love to climb, so if you get a non-wire cage, fill it with climbing material

Two mice need a cage size of at least 60 x 50cm and 30cm tall, but it should ideally be as large as possible. Mice spend most of the day asleep so you’ll need to give them a cosy nest box to curl up in. If you have more than one mouse, they may want to curl up together, but give them the option of their own bed at all times.

Keep their home away from draughts, direct sources of heat and busy areas. Never house your mice with any other rodent or pet, and keep them away from large pets such as dogs who could stress them.

Pet Mouse Housing

Cleaning

This should be done once per week, and even more often for males. They should be given clean bedding, but mix in some of the old so they still have their familiar smell. Use a pet-safe disinfectant to clean their home.

Mice need to mark their territory, so if their cage is thoroughly disinfected too frequently, they may become distressed

Temperatures

Their house should be kept between 18 and 22°C. This way, they can make a nest or sleep to stay warm but won’t naturally overheat

Bedding

Bedding should be put on the floor to absorb urine. Dust-extracted bedding or shredded paper is best as dusty or scented bedding can affect their respiratory system which is very sensitive.

Cedar shavings can cause health problems, and their nest box needs to be filled with shredded tissue paper so they can burrow

Other Products Needed

Mice love two things – to climb and to play. Think tree branches, wooden blocks and houses, small cardboard boxes, ladders, cotton ropes, paper egg cartons or paper towel or toilet paper tubes and small willow balls.

You need to always provide them with water from a bottle, which should be clean and available especially at night when awake.

If you will be letting them out of their cage sometimes, mouse-proof your home or invest in a large closed-in run

They also love to gnaw, and it is important to keep their ever-growing incisors healthy and down. Opt for cardboard, coconut shells, hay cubes, unbleached loofah, pumice stone, seagrass and untreated wood

DIET

Food

Mice are opportunistic omnivores, so mostly eat fruits and vegetables but can also have mealworms, lean meat and pulses as a treat.

Commercial rodent mix is a good basis for a mouse’s diet, too. Give 2 tablespoons per mouse per day, in one or two meals.

This mix topped up with very small portions of carrot and apple and the occasional sprinkling of sunflower seeds is the best standard meal

Safe Foods:

  • Carrot
  • Broccoli
  • Cabbage
  • Cauliflower
  • Chicory
  • Sweet peppers
  • Cucumber
  • Cress
  • Courgette
  • Peas
  • Apple (seeds removed)
  • Pear
  • Peach
  • Melon
  • Dried banana
  • Red grapes

Issues With Diet

Be careful, as it is easy to feed your mouse too much and allow them to get fat, especially if they also eat commercial feed. Sunflower seeds are very fatty so should only be a treat.

If you notice diarrhoea after a certain food, discontinue it. Also, never make any sudden changes to diets – always gradually introduce

Foods To Avoid

Jerry the mouse from Tom & Jerry fame loved cheese. In fact, it is a common myth in cartoons and films. But giving your mouse cheese (or any dairy) can be detrimental to their health.

Also, avoid giving them peanuts, and check the full list of mouse-suitable fruits and vegetables before feeding. Chocolate and any human foods are also bad

Tips For Feeding

The sunflower seeds and small pieces of meat or insects should only be a treat, used as a food topper or for training. Use a small dish for their daily meal, and most can take treats out of your hand as part of their training or encouraging contact

Pet Mouse Care Sheet

HEALTH

Health Checks

Check your mouse over daily. They don’t always like being handled, but it is important for this reason, so find a perfect balance if you want to limit the contact.

You should become familiar with their behaviour and schedule, so you can report any changes straight away. Behavioural changes are often the best way to detect illness, as they may often only show subtle signs of being in pain/distress/suffering until it is serious.

Mice can die if they lose 20% or more of their body weight. For a mouse which weighs 30g, this is only 6g. Consult your vet if they also become overweight, or lose patches of fur

You can weigh a mouse when they are out of the cage during cleaning. Place their small temporary container on some digital scales and tare it

Veterinary Care

Most vets will take mice, as a small pet. Vets will check their teeth, weight and overall signs of health.

Because mice can hate to be transported and out of their natural environment, it is best to limit them being taken only around once per year for their big checkup unless something is wrong.

Don’t delay taking them for worrying about transporting, however – small pets deserve just the same attention as large

Common Issues

Mice don’t live for long, unfortunately, but they can be susceptible to problems associated with ageing. They’re prone to tumours in places like behind the legs and on the neck, as well as mammary tumours.

They can also pick up bacterial or viral infections which cause respiratory issues, especially if they live with several other mice. Ensuring that they have no contact with poisonous or harmful material, such as poisonous food/plants/chemicals, is a very important issue.