A mouse pup is a newborn mouse, completely dependent on its mother for survival. These tiny mammals are born helpless and spend their first days in a state of rapid growth. Over just a few weeks, the pup transforms from a fragile neonate into a recognizable version of an adult mouse.
Physical Development and Milestones
At birth, mouse pups, often called “pinkies,” have translucent pink skin with their eyes and ears sealed shut. Lacking fur, they cannot regulate their own body temperature and rely on the warmth of their mother and littermates. A visible spot of milk in their stomach is often the only sign they have been fed. Within two to four days, the first signs of hair appear as their skin gains pigment.
By the end of the first week, a light coat of fuzz covers the pup’s body and its ears become more defined. A developmental leap occurs around days 10 to 14 when the pup’s eyes and ears open. This sensory awakening allows the pup to begin perceiving the world beyond touch and smell.
Mobility and exploration begin shortly after their eyes open, and around day 12, pups may start to nibble on solid foods. They continue to nurse while transitioning to solids over the next couple of weeks. By three to four weeks of age, they are fully furred, resemble small adults, and are weaned from their mother’s milk, ready for independence.
Maternal Care and Nesting Behavior
A mother mouse ensures her pup’s survival by building a soft, insulated nest from scavenged materials like shredded paper, fabric, and grasses. This nest provides a warm, dark, and protected environment for the vulnerable pups.
The mother nurses her pups for about three weeks, providing all the nutrients for their rapid growth. She also grooms each pup by licking them. This action keeps them clean and stimulates urination and defecation, which they cannot do on their own for the first couple of weeks.
A mother mouse is protective, ensuring the litter stays together for warmth and safety. If a pup squirms away from the huddle, she will retrieve it and carry it back to the nest. This retrieval behavior is an important part of her maternal care.
What to Do if You Find a Mouse Pup
If you discover a mouse pup, first observe it from a distance to determine if it is in immediate danger. Check if the pup feels warm and if a nest is nearby. The mother may simply be out foraging for food and is likely to return.
A pup’s best chance for survival is with its mother. If the pup is warm, uninjured, and you can locate the nest, place it back inside. If you cannot find the nest, put the pup in a small, open container with soft bedding near where you found it, giving the mother a chance to retrieve it. It is a myth that a mother will reject her young due to human scent.
Intervention is necessary if the pup is cold, has visible injuries, or if you know the mother is deceased. In these cases, you should contact a licensed wildlife rehabilitator or a local veterinarian for help. Attempting to raise a wild mouse pup on your own is difficult due to their specific dietary needs and is often unsuccessful.