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The ultimate guide on what to do when you find a baby mouse in the wild
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As you’re taking a walk around your neighborhood, you notice a nest on the ground with a tiny baby mouse inside. The poor thing might be abandoned, but what can you do to care for this sweet baby mouse? When you see a baby mouse all alone in the wild, we know your first instinct might be to take them inside. While it can be difficult, wait a few hours to make sure the mother doesn’t come back. If it turns out the baby mouse is abandoned, we’ve provided you with all the tips and information you need to make them comfortable and feed them. We’ll also cover how to keep the mouse or release them back into the wild. Read on to learn how to care for a baby wild mouse!

Things You Should Know

  • Place the baby mouse in a covered box full of clean rags. Set a heating pad underneath the box to keep the baby warm.
  • Feed the mouse warm kitten replacer milk using a small syringe. Keep them upright and place 1 drop of formula into their mouth at a time.
  • Give the baby 0.05 cc of formula for each gram they weigh. If they’re under 2 weeks old, feed them every 2 hours.
Method 1
Method 1 of 4:

Caring for a Baby Wild Mouse

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  1. If you find a mouse nest with no mother, don’t immediately assume it's abandoned. It’s possible that you inadvertently frightened the mother away or she left to find food to eat. Leave the nest alone and check back after 4 to 6 hours. See if the mother returned by looking for a white band of fur on the baby or babies' bellies; this band shows up when baby mice are full of milk. If they don’t have a band, the mother didn’t return to feed them, and it’s unlikely that she will.[1]
    • Leave the nest as undisturbed as possible. Mouse mothers typically return to their nest even if it’s been slightly messed with, but large disturbances can cause them to abandon their nest.
    • If the mother didn’t return, she is either deceased or has abandoned her nest.
  2. If you find a baby wild mouse or an empty nest of baby mice, call your local wildlife rehabilitation office. Transferring the baby mouse to a wildlife professional is the best chance they have for survival. It might take the rehabilitator several hours or days to collect the baby, so ask them what they recommend doing to keep them alive.[2]
    • If there is no rehabilitation office in your area, your next best option is to hand-feed the baby until they’re mature enough to release.
    • When you call, ask the rehabilitator what they plan to do with the mice. They may try to raise them, or they may use them to feed other animals they are taking care of. If you don't want your baby mouse to wind up as owl food, care for them yourself.
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  3. The bacteria in a cat's mouth can cause a fatal infection called septicemia. Take the injured mouse or mice to your local vet as soon as possible, but know that it is unlikely for the mice to survive.[3]
  4. Keep the baby or babies comfortable by giving them a dark, covered shelter to sleep in. Simply place soft, clean rags in a cardboard box. Trim off any loose threads on the rags that might become tangled around the mouse's legs.[4]
    • Warning: always wash your hands after handling wild mice. They can carry a very dangerous, highly contagious virus called Hantavirus.
  5. A baby mouse has a hard time regulating their temperature, so they need a heat source to stay warm at around 80-100° F (27-38° C). Turn a heating pad to its lowest setting and wrap it in a soft, clean towel or rag. Then, place it under the box where the mouse is resting.[5]
    • Place a thermometer next to the mouse if you’re unsure whether it’s too hot or cold.
    • Be sure the heating pad isn't too hot. If it feels even slightly hot to your hand, let it cool away from the box for a minute before placing it underneath it.
    • If you don't have a heating pad, place a hot water bottle under the box. Or, fill a sock with rice and microwave it for 1 minute. Then, place the sock under the box. Just reheat the bottle or sock when they get cool.
    • A healthy mouse maintains their own body temperature at about 2 and ½ weeks old, as long as their container is in a warm, indoor room.
    • If the baby survives the first few days, transfer them to a glass or plastic ventilated container or small wire cage that they won't be able to chew through.
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Method 2
Method 2 of 4:

Hand-Feeding a Wild Baby Mouse

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  1. Obtain a small feeding syringe. An eye-dropper is too large to feed a small baby mouse. Instead, a baby mouse needs a tiny syringe without the needle. Pet stores often have small syringes with slender, curved spouts specifically for feeding baby rodents.
  2. Rehydrate the baby mouse with a non-flavored electrolyte beverage. Unless you are certain the baby was with their mother less than an hour ago, rehydrate the baby before feeding them formula. Fill the syringe with a non-flavored electrolyte drink, such as Pedialyte. Feed the baby very carefully and slowly by placing 1 drop into their mouth at a time, stopping once they’ve had 3 to 4 drops. Then, wait an hour before feeding the baby formula.[6]
  3. Determine the baby's age by looking at a growth chart. In order to feed the baby mouse the right amount and on the correct schedule, find out how old they are. Consult a chart that shows photos of a baby mouse as they develop, and match your mouse to one the same size in the pictures.[7]
    • Baby mice start growing fur at about 3-5 days old.
    • Baby mice open their eyes at around 10-14 days old.
    • After a baby mouse opens their eyes, they enter the “flea” or “popcorn” stage. At this stage, they jump around a lot and are difficult to hold.
  4. Feed the baby warm kitten milk replacer while holding them upright. Prepare the formula in a bowl according to the package's instructions. Then, warm it in the microwave using 30-second intervals, testing it to make sure it's warm, not hot. Fill up your syringe and grasp the baby gently around their middle with their head at the top of your fingers. Slowly dispense the formula into the side of the baby’s mouth 1 drop at a time.[8]
    • Alternatively, use a puppy milk replacer like Esbilac or a human milk replacers without iron, like Enfamil, Isomil, or Soyalac.
    • If the baby mouse is having trouble drinking the formula, water it down by adding twice as much water.
    • If the mouse is extremely small, use a new, clean fine-tip paintbrush instead of a syringe. Dip the brush into the formula, then dab it into the corner of the baby's mouth.
    • Keeping the baby in a vertical position prevents aspiration, which is when liquid gets into their lungs and causes them to suffocate. Never rest the baby mouse on their back when you feed them.
    • If you see a bubble come out of the baby's nose while feeding, immediately flip them upside down (tail up, head down) to prevent any more liquid from getting into their lungs.
    • Sadly, a young baby mouse is unlikely to survive aspiration. There is a very slight chance that an older baby will survive if you turn them upside down immediately.
  5. Give the baby mouse about 0.05 cc of formula for each gram they weigh. For example, a 10 gram (0.3 oz) baby mouse needs 0.5 cc of formula every time they feed. Just place the baby on a kitchen scale to find out how much they weigh. Then, use the cc measurements on your syringe to give the right amount of formula.[9]
    • Look for the white band on the baby mouse’s belly to check if they’re full.[10]
    • Dab the baby’s face with a cotton swab after each dose of milk to keep the airways clear.
    • If the baby appears to be losing weight, increase the amount of formula you give them.
    • Never force the baby to eat. Instead, feed them slowly and gradually.
  6. An abandoned mouse may actually be a little older than they look because they are underfed and malnourished. Because it’s often hard to tell how old they really are, just feed the baby according to the age they appear to be. In general, mice are fed in intervals according to their age:[11]
    • If the baby mouse’s eyes are still closed, feed them about every 2 hours, morning and night. At this stage, they’re between 0 to 14 days old.
    • When the baby's eyes open at around 2 weeks old, feed them every 3 to 4 hours.
    • When the baby is about 3 weeks old, they’re ready to eat solid foods.
  7. Baby mice don’t urinate and eliminate their bowels on their own. If they aren’t encouraged to go, their waste builds up which can lead to death. After you feed the baby mouse, gently rub their belly, genitals, and anus with a fluffy cotton swab soaked in warm water for about 1 minute.[12]
    • Be careful not to rub too hard or too much that you irritate the baby's skin.
    • If the baby mouse doesn’t use the bathroom after several minutes, let them rest. Come back in about 30 minutes to try again.
    • Warning: wash your hands after touching or holding the wild mouse. Mice can carry Hantavirus.
  8. Once the baby is 2 to 3 weeks old and has opened their eyes, add solid mouse food to their formula feedings. Place a small dish full of little bits of solid food so they have something to nibble on. Then, continue to offer them formula until they’re about 3 ½ to 4 weeks old.[13]
    • Suitable hard foods include: premixed rodent food (hamster food is best), cooked rice (they usually prefer white over brown rice), human baby food, kitten food, apples, carrots, and seeds.
  9. Give a mature baby mouse a water bottle. When the baby has opened their eyes and is old enough to eat solid food, they need to stay hydrated with water. Hang a rodent water bottle on the side of their enclosure or cage, with the tip of the spout low enough that the mouse can reach it. Allow the mouse to find and use the water bottle on their own—it's okay if they don’t want to use it at first.
    • Don't give the mouse water in a bowl as they can easily drown.
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Method 3
Method 3 of 4:

Placing the Baby with a Foster Mother

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  1. If you have a domestic mouse with babies roughly the same size as the wild mouse, encourage the mother to take care of them. Lure the mother mouse out of her nest and put her in a separate cage or enclosure so she can't see what you're doing.[14]
    • Fostering is less risky than hand-feeding a baby that is less than one and a half weeks old, which is about the time they first open their eyes.
  2. This makes the baby mouse’s scent seem familiar, which increases the chances of the mother taking in the baby mouse as her own. Just very carefully rub the baby mouse with bedding from the mother mouse's cage.[15]
    • Warning: always wash your hands after touching the wild mouse as mice can carry Hantavirus.
    • Use only clean bedding – soiled bedding materials can harm the baby mouse.
  3. Gently place the baby wild mouse in between and underneath the mother’s babies. Touch the babies as little as possible when you nestle the wild mouse next to them.[16]
  4. Place the mother mouse in her cage, slightly away from the nest. Allow her to find the babies on her own—don't force her to join the group.[17]
  5. Do not hover over the cage to watch the mother and her babies or disturb the mice in any way. If the mother feels stressed out, overwhelmed, or upset, she might abandon all of the babies.[18]
    • You will hear loud squeaks if something bad happens, so there is no need to watch the cage.
  6. If you need the mother to foster several wild baby mice at once, she might not have enough milk to feed them all. Coax the mother away from her nest several times a day and place her in a separate tank. Hand-feed the babies the same way you would feed an orphaned baby mouse.[19]
    • If the babies have “milk bellies” (a visible white band or area on their stomach, which is the actual milk in their tummy), they are getting enough milk from the mother without your help.
    • Check the babies several times a day during the first few days to make sure they have milk bellies and are not losing weight. Babies lose weight very quickly so they need to be fed right away.
  7. If you don't have a mother mouse, you may be able to buy one that has recently given birth, along with her babies. If you have a very young baby mouse, their chances of survival are much better with a foster mother than if you hand-feed them yourself.[20]
    • Moving the mother and her babies carries the risk of the mother abandoning her babies, so weigh the risks very carefully before trying it.
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Method 4
Method 4 of 4:

Releasing the Mouse Back into the Wild

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  1. If you keep the mouse indoors, they’ll be shocked when it comes time to release them outside. When they’re around 3 weeks old, move their cage close to an open window so the mouse hears the outdoors. Then, slowly move their enclosure outside for several hours during the day. By the time they’re 4 weeks old, let them spend about half of their day outside in their cage.[21]
  2. If the baby wild mouse you’re looking after is healthy and is still skittish around you, it’s best to return them to their natural habitat. Just make sure they’re mature enough to release, which is typically when they’re 6 weeks old or weigh 12 grams (0.4 oz).[22]
    • This is a rough release guideline, so monitor your mouse’s progress to ensure they’re ready to release. If they’re easily eating hard food, running fast, and aren’t afraid to bite you if you get too close, they’re likely ready.
    • Do not handle the mouse often or play with them to ensure they stay frightened of humans.
    • If you release a wild mouse before they’re old enough, they might not have all the skills they need to survive.
  3. Find a location that has lots of trees, rocks, bushes, and water nearby. Wait for a day with good weather to help ensure the mouse survives in the wild. Then, go to the location and find a covered, protected area, such as by some bushes, underneath a tree, or around leaf litter. Gently tip the mouse out of their enclosure in the covered area and watch them scamper off.[23]
    • Place some food near the covered area to give the mouse some support as they get used to their new home.
    • If you were taking care of multiple babies, release them all at the same time.
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Tips

  • Feeding the mouse too much or too often can cause diarrhea, which can lead to dehydration. If the mouse starts getting diarrhea, switch to giving them electrolytes, like Pedialyte, to hydrate them. Once it stops, switch back to formula.
  • If you are looking after several babies, keep them together in the same enclosure. Mice are social animals and like to stay around their siblings.
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Warnings

  • Always release an adult wild mouse back into the wild. It is cruel to keep them because they will never lose their fear of humans, no matter how much they are handled.
  • Wild mice can carry the deadly Hantavirus, along with fleas, ticks, and worms. This is typically less common with baby mice, but handle them with care and wash your hands thoroughly after you touch them.[24]
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Things You'll Need

Caring for a Baby Wild Mouse

  • Small box with ventilation holes
  • Fish tank or small rodent cage
  • Bedding materials (unscented toilet paper or kleenex, clean rags, or paper towels)
  • Heating pad or hot water bottle

Hand-Feeding a Wild Baby Mouse

About This Article

Alisa Rassin
Co-authored by:
Exotics Veterinarian
This article was co-authored by Alisa Rassin and by wikiHow staff writer, Devin McSween. Alias Rassin is an Exotics Veterinarian and the Owner of The Exotic Animal Hospital of Pennsylvania in Lansdowne, Pennsylvania. With over a decade of experience, she specializes in treating reptiles, birds, and small mammals. She holds a Veterinariae Medicinae Doctoris from The University of Pennsylvania and a BS in Veterinary Biomedical and Clinical Sciences from Penn State University. She was also certified by the Royal College of Veterinary Surgeons. This article has been viewed 531,917 times.
51 votes - 94%
Co-authors: 13
Updated: November 14, 2024
Views: 531,917
Categories: Mouse Health
Article SummaryX

If you encounter a baby wild mouse, wait at least 1 hour to see if its mother returns before you try to save it. If the mother doesn't return, call a wildlife rehabilitator to come rescue it. In the meantime, line a small box with clean rags and carefully place the mouse in it. Make sure you wash your hands right after handling it. If it’s warm out, leave the box outside while you wait. If it’s cold, take the box indoors and place it on a heating pad set to low to keep the mouse from getting too cold. If the mouse’s eyes are closed, you should feed it right away. Mix 4 1/2 cups (1070 mL) of water with 2 teaspoons (8 g) of sugar, ½ teaspoon (3 g) of salt, and ½ teaspoon (3 g) of baking soda. Use a soft-tipped syringe to carefully push some of the mixture into the mouse's mouth. If you don't have a syringe, use the bristles on a clean, small paintbrush to feed the mouse the mixture. Give it a few drops every 2 hours while you wait. If the mouse’s eyes are open when you find them, feed it small pieces of vegetables, fruits, or seeds instead. Keep in mind that it's not recommended to keep a wild mouse as a pet since wild mice aren't domesticated and often carry diseases. A wildlife rehabilitator will be able to rescue the mouse and release it when it's healthy. For tips on how to foster a baby wild mouse with another mother, read on!

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