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Mice/What is wrong?


I have a very young mouse (about 4 weeks old) who is not very happy at the moment. Is cold to the touch and seems sleepy. Is eating fine but is looking a little gaunt. It might be the way (s)he's sitting though.
Not very energetic, unlike siblings, and is very quiet and doesn't interact with the other mice. Because (s)he is cold I have the mouse in my hand but I dont know is this is a good idea or not. I sincerely hope that they are not going to die.

Hi Zoe,

What are they eating?  At four weeks, most mice are not able to drink on their own, so if they are eating mouse food they will still need to be well hydrated through dropper-feeding or paintbrush-feeding it kitten or puppy milk replacement.  You can also offer soft, moist foods with his current diet, such as fruit based baby foods, scrambled eggs made with kitten/puppy milk replacement instead of cow's milk, or stale bread soaked in water or the KMR.

It could be dehydration, or it could be illness or something called "failure to thrive" (a catch-all term referring to any disorder, congenital defect, or disease that causes sudden decline before maturity).  There is no way to diagnose anything this young, however, without the help of a vet, and there are extremely few safe medications available to juvenile mice.

Is there a veterinarian in your area who works with mice?  If so, that would be the mouse pup's best shot at life.  Pups are HARD, even when everything goes right, so if there is a professional you can have look at it, please do.  If no vet is available, you can also try reaching out to local wildlife rehabilitators (obviously only if they work with small rodents), mouse breeders, or exotic animal rescues.

In the meantime, keeping it warm is a good plan.  I'd also suggest getting a food scale that measures in grams and measuring before and after every feed, or if you are no longer supplementing, five to six times a day.  You can put a wash cloth in a high sided bowl and tare the scale before adding the mouse.  At this age, he should be gaining every single day.  No gain is a concern, and weight loss is an emergency.  If hydrating does not fix the problem, there might not be much you can do.

Best of luck to the little guy (or girl).  Please let me know if there is anything else I can help with.



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I can answer questions regarding mice as pets, mouse behavior, color and coat genetics, breeding techniques, and general health questions. I can help with caging and setup, nutrition, social issues, and what to do in most mouse emergencies (such as unplanned litters, injuries, fighting, etc.). I can also assist with questions pertaining to orphaned mouse pups, weaning litters, and questions of mating and birthing. I cannot answer questions about exotic or wild varieties of mice such as spiny or pygmy mice. *****FOR EMERGENCIES, anything requiring immediate medical intervention, PLEASE take your mouse to a professional veterinarian or wildlife rehabilitator who works with mice as soon as possible! IMPORTANT RESOURCES: Raising Orphaned Mice: Orphaned Mice Videos: Natasha's Your First Mouse: General Mouse Help: Mouse Info and Exotic Breeds:


I have enjoyed the companionship of mice nonstop since 2004, and spent a year caring for them in a lab where I learned a great deal about their breeding, social needs, and health. I spent a few years breeding them, specifically working with albinos, marked mice, angora mice, and satins. My education never stopped - I am learning something new every day from current and well-established research thanks to the wonderful folks at the Jackson Laboratory, as well as from my wonderful mousey friends online. I also love learning from my terrific questioners here on AllExperts - you folks keep my passion for these amazing animals alive and well!

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