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How Many Babies Do Mice Have In a Litter? Everything You Need to Know!

Nicole Cosgrove

You may think mice are cute, especially when eating cheese with their tiny hands. However, when they infest your home, they are nowhere near cute. If you notice a mouse in your house and instead of dealing with it you decide to wait for it to die, think again.

Mice are infamous breeders. One female can give birth to 20 to 60 babies in a year. And at this point, you will have a mice infestation.divider-mouse

How Long Do Baby Mice Stay with Their Mother?

A female mouse carries her pregnancy between 19 to 21 days. When she gives birth to her litter, it consists of 6 to 12 mice and can give birth five to six times a year. Additionally, she can mate immediately and birth the next little when the baby mice are around 25 days.

Birth of a Mouse

The baby mice are born without ears, fur, and sight. Since they are deaf and blind, the mother nurses the litter for 21 days. During the early nursing days, the pups grow rapidly. By the fourth day, they have fully developed ears. On the sixth day, fur begins to sprout, and by the 10th day, they have a full coat of fur.

Until the 13th or 14th day, the pups never open their eyes, and to this day, they are almost grown adults. The female mice wean on the 21st day when the male pups leave the nest while the females stick around. Regardless of the sex, on this day, they are ready to start chewing your possessions.

How Long Do Mice Live?

mice
Image Credit:Piqsels

A female mouse can start producing pups as early as six weeks old. Their quick maturation gives them high breeding capabilities. Additionally, living indoors increases these capabilities since they can breed all year round.

If the mouse is living outdoor, they only breed during spring, fall, and summer. And just like their litter increases when they live indoors, they also increase their life span. While an expected outdoor lifespan is 12 months, the number rises to 3 years if indoor.

Why the increase? Indoor mice are not exposed to natural predators and harsh weather conditions. So, all they do in your house is to eat, breed, and spread diseases.

What Might Keep These Numbers Down?

One reason why nature has ruled positively on the large numbers of pups in a litter is the many environmental factors that affect young ones. Lack of food and shelter means only the strong ones survive in such situations.

Additionally, mother mouse may devour her pups for two reasons:

  • If the resources are limited, the mother eats the pups that seem weak to reduce competition among the pups.
  • When a mother mouse eats her pups, she gets unique calories that allow her to gain strength to survive and carry another pregnancy soon.

For mice, they adhere to the survival of the species and not individual survival. The father mouse takes the above decree seriously by ensuring that he passes his genes to the pups. For instance, if a male pup suspects that his mate’s pups belong to another male, he will kill all the pups, or only those he suspects are not his own.

In most cases, he doesn’t have to wait for the pups to be born. If a female separates from her mate when pregnant, she aborts the pregnancy if a new male joins her territory. Scientists believe that the male releases pheromones to trigger abortion. This is known as the Bruce effect.

mice
Image Credit: Kapa65, Pixabay

Signs of Mice Infestation

You can easily spot mice in your home in the cold seasons. Once a mouse enters your home, it can cause several problems, including allergies and asthma, food contamination, and other diseases. What are the signs of mice infestation?

  • Unusual Noise at Night – Mice make noise when moving within the walls in your home.
  • Droppings – You will notice mice droppings, especially in food storage such as pantries and cabinets. You can also spot droppings in cardboard boxes, on the wall beams, under the sink, or baseboards.
  • Nests – Mice make their nests with cotton, wall insulations, paper products, or fabric in secluded areas. They also love dark spots where you can’t bother them.
  • Gnaw Marks – Mice can chew through any material especially lead pipes and plastic. When mice are in search of food, they will destroy everything.
  • Mouse – This is an obvious sign. Of course, if you spot a mouse, there is a high chance others are in your home since they breed at a high rate.

How to Prevent Mice from Making a Nest

mice habitat
Image Credit: Karsten Paulick, Pixabay

How can you discourage mice from invading your home? The best way is to make your home as unattractive to them as possible. Ensure that there are no conditions that favor forming a nest and living in your home.

  • Seal all food packages and keep the kitchen clean.
  • Keep your garbage clean and check the garage and car engine for nests regularly.
  • Discard old cardboards, and if you need storage boxes, use metallic or plastic solid boxes.
  • Discard old clothes and if they are seasonal, store them in a rodent-proof area.
  • Seal all possible entries around your houses, such as pipes, cracks, or electrical outlets.

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Final Words

So, what should you do if you discover a nest in your home? Well, first, never touch it without protective gloves and put on a face mask.

Place the nest in a bucket in case there are pups still in the nest. If you find pups, do not kill them; instead, take them in the woods away from your home and burn the nest. Ensure that you clean any droppings with bleach and water to kill bacteria.

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Featured Image Credit: Eric Isselee, Shutterstock

Nicole Cosgrove

Nicole is the proud mom of Baby, a Burmese cat and Rosa, a New Zealand Huntaway. A Canadian expat, Nicole now lives on a lush forest property with her Kiwi husband in New Zealand. She has a strong love for all animals of all shapes and sizes (and particularly loves a good interspecies friendship) and wants to share her animal knowledge and other experts' knowledge with pet lovers across the globe.