If you’ve found baby mice, the most important first step is figuring out whether they actually need your help. In most cases, the mother is nearby and will return. Acting too quickly can do more harm than good, since a mother mouse will often avoid her nest if she detects human scent or disturbance nearby. Before you intervene, take a breath and assess the situation.
Determine Whether They’re Truly Orphaned
Mother mice leave the nest regularly to find food and water. An empty nest doesn’t mean abandoned babies. The Toronto Wildlife Centre recommends leaving baby mice undisturbed for one full overnight period to give the mother a chance to return. If she hasn’t come back by the next morning, the pups are likely orphaned.
During this waiting period, avoid handling the babies or hovering near the nest. Check from a distance if possible. You can place a few small pieces of string or thread across the nest entrance. If they’ve been moved by morning, the mother was there.
Estimate Their Age
Knowing roughly how old the pups are helps you understand how urgently they need care and what kind of help they require. Newborn mice are tiny, pink, hairless, and have their eyes sealed shut. Here’s what to look for:
- Days 1 to 3: Completely hairless and pink, eyes closed, barely mobile. They cannot regulate their own body temperature at all.
- Days 4 to 7: A light fuzz of colored fur begins to appear. The belly starts showing fur around day 7. Eyes may begin to crack open around day 3 or 4.
- Days 9 to 11: Fur is noticeably thicker and nearly complete. Pups become more active and start moving around.
- Days 12 to 14: Eyes are fully open. Pups are mobile and beginning to explore. At this stage, they may be close to weaning.
Hairless pups with closed eyes are the most vulnerable and need warmth immediately. Older pups with full fur and open eyes have a much better chance, even without intervention, and may be close to surviving on their own.
Keep Them Warm First
Baby mice, especially hairless ones, lose body heat extremely fast. Hypothermia will kill them before hunger does. If you’ve determined the pups are orphaned, place them in a small container lined with soft cloth or tissues. Set this container on top of a heating pad on its lowest setting, or place a warm water bottle (wrapped in a cloth so it doesn’t burn them) next to the container. The goal is gentle, steady warmth without direct contact with a heat source. Leave part of the container unheated so the pups can shift away if they get too warm.
Contact a Wildlife Rehabilitator
Your best option for orphaned wild mice is getting them to a licensed wildlife rehabilitator. These professionals have the tools, formula, and experience to raise fragile pups that are extremely difficult to keep alive by hand. Most state wildlife agencies maintain a directory of licensed rehabilitators you can find online or by calling their helpline.
When transporting the mice, place them in a ventilated cardboard box in a dark, quiet, warm spot. Don’t try to feed them before making contact with a rehabilitator. Improper feeding, especially with cow’s milk or human infant formula, can cause fatal digestive problems. Follow whatever instructions the rehabilitator gives you over the phone.
Be aware that not every rehabilitator accepts mice. House mice in particular are considered an invasive species in most of North America, and some facilities won’t take them. If you can’t find a rehabilitator willing to help, you’ll need to decide whether to attempt care yourself or let nature take its course.
Emergency Feeding if No Help Is Available
Hand-raising newborn mice is extremely labor-intensive and has a low success rate, but it’s possible. The key details: use powdered puppy milk replacer (not kitten formula, not cow’s milk), mixed according to the package directions. One lab protocol that has been used successfully calls for 9 grams of powdered puppy milk per 30 milliliters of warm water.
Feed the pups every two hours around the clock using a tiny syringe, a paintbrush dipped in formula, or a purpose-made nursing bottle for small animals. Go slowly. Mice this small can aspirate liquid into their lungs with even a slightly too-fast flow, which causes pneumonia and death. After each feeding, gently stroke the pup’s lower belly and genital area with a warm, damp cotton swab. This mimics the mother’s licking and stimulates them to urinate and defecate. Without this step, they can’t eliminate waste on their own.
The every-two-hour schedule is demanding. It means setting alarms through the night for potentially two weeks until the pups are old enough to eat solid food. By around 14 days, mice with open eyes can start nibbling softened rodent pellets or oatmeal, and you can gradually increase the time between formula feedings.
If You Found Them Inside Your Home
Finding baby mice in your house means there’s an active mouse nest, and the mother is living in your walls, attic, garage, or crawlspace. This is a different situation from finding wild pups outdoors. House mice reproduce rapidly, and a nest of pups signals an established presence.
If you want to remove them humanely, wait until the pups are mobile and furred (roughly two weeks old) before sealing entry points. Trapping and relocating adult mice is largely ineffective. CDC research on deer mice found that relocated mice returned to the original house within 24 hours, even from distances of 500 meters or more. One mouse returned repeatedly after being released over a kilometer away. The animals navigated around rocky outcroppings, winding roads, and predator territory to get back. Mice with prior homing experience returned 100% of the time.
The more effective long-term approach is exclusion: sealing every gap and hole in your home’s exterior. Mice can fit through openings as small as a pencil’s width. Steel wool stuffed into gaps, caulk, and metal flashing over larger holes are the standard tools. Remove food sources that attract them, including pet food left out overnight, unsealed pantry items, and bird seed stored in garages.
Protect Yourself During Cleanup
Wild mice carry diseases transmissible to humans, most notably hantavirus, which spreads through contact with rodent urine, droppings, and saliva. Dried droppings that get stirred into the air are the primary risk. Never sweep or vacuum a mouse nest or droppings, as this sends particles airborne.
The CDC recommends spraying the nest and surrounding area with a disinfectant or bleach solution before touching anything. Mix 1.5 cups of household bleach into 1 gallon of water (roughly 1 part bleach to 9 parts water). Spray the area until it’s thoroughly wet and let it soak for at least 5 minutes. Then pick up materials with gloved hands, place everything in a sealed plastic bag, and dispose of it in a covered trash can. Wash your hands and any clothing that made contact.
If you handled the baby mice directly, wash your hands thoroughly with soap and warm water. The risk from brief contact with pups is lower than from cleaning up nesting materials and droppings, but gloves are always a good idea when dealing with wild rodents of any age.