How Many Babies do Mice Have? 5 Things to Consider

A single mouse can give birth to a litter of 5 to 10 baby mice at once. They can give birth up to 10 times every year.

The average number of babies a female mouse can produce throughout her lifetime is between 50-150. However, it is not rare that one female gives birth to 300 of them in her lifetime.

Only about 20 days need to go by and your mouse will be ready to breed again. Pet mice have interesting personalities, they are fun to interact with and easy to take care of at home.

If you want to breed them, then you need to clean the cage more frequently and perform maintenance.

How to Tell if a Female Mouse is Pregnant?

You can tell if your female mouse is pregnant if she looks like she swallowed a ping-pong ball. At this point, there is nothing to be afraid of.

Once the babies are born, they won’t require any special care. Their mom will take care of everything they need, you just need to make sure not to disturb them.

You don’t necessarily have to notice that your mouse is pregnant at an early stage. It is enough to notice it right before your female mouse gives birth.

After all, there is no list of things to do once she gives birth. Pretty much the only thing you need to do is to thoroughly clean the cage one last time before it happens.

From then on, both the mother and her little babies are going to be fine.

How to Care for a Pregnant Mouse?

If you notice that your female mouse is pregnant, you need to start to feed her more. She also needs more water throughout her pregnancy.

Make sure that the cage is not placed at a noisy spot and that there are no kids or other animals to bother them.

It is all about creating a stress-free environment for the pregnant mouse. She has to be able to gain some additional calories and eventually give birth without anyone disturbing her. Keeping her in the children’s room where the kids usually play is a really bad idea for example.

If nothing else works, then you might even need to take the cage to the basement where they are exposed to almost no noise.

Keep in mind that if a pregnant mouse feels threatened, she might eat her babies out of sheer stress. It is worth choosing the safe route and wait until those little guys get bigger.

Do Mice Care for Their Babies?

Baby mice are completely safe as long as they are on the side of their mom. Give the female mouse some extra food besides her usual portion and she will take care of the rest. It is very important not to make the mother threatened. This is why you need to keep them in a calm environment until the babies grow up a bit.

In case the female feels threatened, she can decide to eat the babies and it’s not going to be pretty. Don’t stay near the cage for too long and don’t let your children or other pets near it. She is going to feel safe if nothing unexpected happens around the cage.

You will notice if the mother eases up a bit and wants to play. In that case, she is going to approach you and act curious.

What to Do if Your Mice has Babies?

Once the little babies are born, you should avoid cleaning the cage near the nest for a while. The mother and her babies should not be disturbed. Also avoid touching those little guys because it will only cause the mother to be confused of the scent.

You can touch them, but only if you really have to. In that case, pick up some bedding from the cage and dust your hands with it. This will help you cloak your natural odor.

Wait until the babies open their eyes before you perform any thorough cleaning in the cage.

They usually open their eyes after about a week. Even then, divide the cage into small portions and clean it bit by bit in order to not disturb them in the process. The longer they stay in the cage, the more important it becomes to replace the bedding too.

These little guys depend on their mother for about four weeks. It won’t take them long to become fertile after this period.

How Often do Mice Have Babies?

As we mentioned, it takes about 19 to 21 days for a female mouse to give birth to her babies from the first day of pregnancy.

A litter of pups consists of about 10 individual babies. Mice can repeat this whole process about 10 times every year, giving birth to an average of 100 babies per year.

Simply put, mice are breeding machines and nothing can stop them from reproducing if you leave them in one cage.

Remember that it takes around five weeks until a mouse becomes fertile if you count the days from its birth. If you are not careful, there are going to be a lot of mice in the cage in a couple of months.

Basically, female mice can give birth to a litter of babies every 25 days until they die.


We can conclude that mice can produce an insane number of babies in their lifespan. If you keep a male and a female, it takes only a couple of months until you can witness some serious exponential growth in their numbers.

Breeding mice is easy, as there is literally nothing to do except to ensure a calm environment for the mother.

She will take care of the rest and make sure that her babies are safe for that 3-4-week period. If you want to become a mouse breeder yourself, then go ahead.

All you need to do is buy enough food for your mice and keep the cage clean as best as you can.

avatar Jane
Jane is an experienced animal care specialist with a focus on rodents and small mammals, with over 10 years of experience in the pet industry. Her articles provide practical guidance on choosing the right pet and managing common health issues. Jane is an advocate for animal welfare and supports organizations dedicated to protecting wildlife. read more...

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