Wild baby mouse found

Question
Hello there! This afternoon around 12, I was at a town park that also is on the water with its own little beach area. When walking one of my friends saw a baby mouse just laying there, not moving at all, eyes and ears closed but furry. After 40 minutes he was still in the same spot and no mama in sight so I decided to take him home and stop at the pet store for KMR, a teeny eye dropper, bedding and a cage. I began feeding the baby as soon as I got back, only feeding it what it would take and I did this every hour to two hours for 15 hours (also stimulating bowel movements/urinating). I just woke up at 230 am after the last feeding at 11:50-12am. I saw pee and some feces in the cage and thought this is great! It might be getting better! So I fed him and rubbed a warm damp qtip on his genitals and he urinated for me so I put him back in his cage, with the warm rice sack I had made for him to snuggle up to. I heard him making a weird suckling noise and moving his hands so I thought he might be hungry and I turned around and he had died. What happened in the 2 seconds I turned around?  I had kept the cage on a heating pad at a low temp with an old t shirt between the cage and heating pad too. This is my first baby mouse ever so I'm pretty sad he didn't make it through the night. Thanks for any insight!

Answer
Hi Kirsten,

I'm so sorry to hear that, how awful!  :(  It sounds like you did everything perfectly - there is nothing I could tell you to change or add when it comes to taking care of orphaned mice.  Actually, you sound like a natural!!

Unfortunately, even when everything is done right, pups are just so fragile that any number of things can go wrong while they are developing and still tiny.  You mentioned he was all by himself when you found him, just lying there - this tells me something was wrong before you found him.  Sometimes moms will kick babies out of the nest if they know something is wrong (don't ask me how they know, but they do!).  This could mean something was genetically impairing, that he wasn't thriving like his siblings, some kind of immunodeficiency, a lethal gene, any number of things that would be tough to tell without comparing him side by side with the rest of his litter.  That he was doing so well before he passed proves there was something else going on before you found him - your care made the last of his little life happy and warm.

Another possibility is that he could have been lost from the nest (such as when a nest is built in something someone moves, and a baby tumbles out) or pulled by a predator, and there is no way to tell how long he may have been laying there with potential internal injuries.  Anything could have gone wrong unfortunately before you got there, that may have just taken a toll on his fragile little system.  There really is no way of knowing, but again, you made his last day a wonderful one!  I am so glad he had you.

I wish I could tell you more specifically what could have gone wrong, but at least I can assure you that whatever went wrong wasn't while he was in your care.  Even a necropsy with a pathology at his age wouldn't let you know if it was genetic, unfortunately.  Don't let this discourage you - you really did do wonderfully.

-Tam