Mice and Rats
The mouse life cycle
Learn about the average mice lifespan and life cycle of these small rodents.
Updated: April 30th, 2025
Mice may be small, but their ability to reproduce fast makes them a significant threat to homeowners. Understanding the mouse life cycle is crucial for preventing a mouse infestation from taking over your home. Learn about mice and how quickly they grow, reproduce, and spread so you can take steps to protect your property.
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How many babies do mice have? How many mice are in a litter?
Prevent a mouse infestation in your home
The stages of a mouse’s life
How long do mice live? We’ll walk you through the whole mouse life cycle from when mice are born into adulthood:
Newborn pup stage (birth to 21 days)
In these first three weeks of a mouse’s life, pups are completely dependent on their mother for warmth and nutrition. By the end of this stage, they are rapidly on track towards adulthood.
Characteristics:
Mice are born blind, deaf, and hairless
Ears develop by day 4
Fur starts growing around day 6 and fully develops by day 10
Eyes open around day 13-14
Nursing continues until weaning on day 21
Juvenile stage (after 21 days to 6 weeks)
Juvenile mice are now capable of surviving on their own. They begin chewing and foraging, which can lead to damage around your home.
Characteristics:
Start foraging for food independently
Rapid growth and development of motor skills
Males often leave the mother’s territory, while females may stay longer
Adult stage (6 weeks and beyond)
Adult mice are focused on nesting and reproduction. Once mice reach adulthood, their population can boom and become a large infestation.
Characteristics:
Fully grown and sexually mature
Start reproducing as early as 6 weeks old
Lifespan averages about 12 months in the wild and can survive as long as 2 to 3 years indoors
How long do mice live?
At 6 weeks old, the female house mouse is sexually mature and ready to start producing pups of her own. This quick maturation process gives mice immense breeding capabilities. Living indoors enhances these capabilities since they can then breed all year long. In the outdoors, breeding can occur all year long in Southern and coastal areas.
And just like the breeding output increases if a mouse takes refuge in your home, so does the length of their life. While the average mouse lifespan is only about 12 months outdoors. Indoors, this number can climb to 2 to 3 years. This is because, indoors, mice aren’t exposed to harsh environments or natural predators. That leaves them with nothing to do but eat through your valuables, spread disease to your family, and breed future generations to carry on the scourge.
How many babies do mice have & how many mice are in a litter?
Mice are prolific breeders, which is why infestations can grow so quickly. Their rapid reproduction cycle is why the beginnings of a mouse problem need to be dealt with as soon as possible.
Gestation period: About 19–21 days
Litter size: Typically 5-6 pups per litter, but can get as high as 12 in a litter
Litters per year: A single female can birth between 5 to 10 litters a year
Lifetime offspring: A single mouse can give birth to up to 300 pups over a 2- or 3-year lifespan
Prevent a mouse infestation in your home
As you can see, a pair of mice can quickly go from no big deal to trouble for your home. Stop the life cycle of a mouse with mice control solutions for your home, indoors and out. Book your free mice inspection today with Terminix and our experts will put our most advanced techniques to target and eliminate mice fast.
