For a short answer, pet mice bred and kept in captivity usually live between 1.5 to 2 years in age. Obviously there are a number of factors that will contribute to either end of this scale. Additionally, there are always exceptions. I have heard stories from mice owners claiming they have had mice pass the 3 year mark.
Taking good care of your mice can increase the pet mice lifespan. Obviously there are no guarantees over such things, but common sense tells us that a happy, healthy mouse is more likely to live a longer life.
Do not Overfeed
Overfeeding our pets is tempting and easy to do. We need to exercise some discipline on behalf of our pets and not feed them too many treats. Obese pets in general is a global problem, and mice are no different, If you put too many treats out and not follow a strict diet plan of nutritional foods you run the risk of making your pet overweight,
It’s worth remembering that while these are not wild pets, they do come from a lineage of wild mice. Wild mice have to fend for themselves and often have to travel a great distance to find food. In the wild, mice would almost certainly be getting more exercise and less food than they will in their comfy captivity. That is not entirely a bad thing, most of us would enjoy a comfy life, but some common sense goes a long way when handing out treats if you want to maximize your pet mice lifespan.
Consult a Veterinarian if your Mouse is Sick
If for any reason you believe your mouse to be sick then you need to consult a veterinarian as soon as possible. If you mouse is loosing weight it can be very dangerous, loosing 20% or more of their bodyweight can be fatal. Look for signs of behavioral changes, loss of weight, shortness of breath or labored breathing,
Never try to diagnose or resolve a health problem yourself. Always consult a professional, sometimes this may mean ringing around local practices to find a vet who specializes in rodents. There are some resources available on the RSPCA’s web page and help obtaining contact information.
Separate any Aggressive Mice
Reducing any stress, trauma or bodily injuries will almost certainly extend the lifespan of your mice. If you have more than one male mouse its not uncommon for one or more mice to be bullying the others. You will first be aware of this when you hear squealing noise from the mouse being attacked and see or hear some rapid movement.
Unfortunately I can tell you from experience that an aggressive mouse rarely, if ever, changes its behavior. you really only have one option, and that is to separate the offending mouse. Leaving it with the others to see if the attacking stops is not a good idea, this just allows more physical damage to happen to the others. Separate the mouse into a completely different cage away from the others, while this is not convenient it is one of the challenges of owning pet mice that might be necessary,
Allow Mice to Exercise
Make sure you mice have a large living space, mice need exercise like any other pet animals. You can put a hamster wheel in their cage and often they will use this. I tend to make a series of obstacles, usually out of cardboard and tubes and let them run around. Also, if you can, let them out of the cages sometimes, you can buy a ball for them to run around in or prepare a safe area where you know they will not be able to escape and disappear.
Be prepared for your mice to make noise at night as they are nocturnal creatures, although if their cage is in a separate room to where you sleep its unlikely you will hear them or be disturbed. Providing your mice with a stress free environment where they can exercise when they choose to will almost certainly be a factor in maximizing your pet mice lifespan.
I have kept pet mice for a number of years and always had a fascination with these interesting, fun little creatures.
I'm always looking for new and interesting mice related information and will always help other mice owners where possible.