Mouse died

Question
Hi there, my daughters mouse died this morning, I just wanted to ask I about the remaining boy. Both of these boys were born from a pet shop mouse who was pregnant when we got her but didn't know. She had 6 babies, 4 girls and 2 boys. One of the girls was very tiny and diied within 2 months. This boy wasn't very big but was very healthy and suddenly died without any sign of illness and was only 6 months old. When I took him from the cage his belly was very dark and bloated and I wondered if the darkness could be blood? Is the other boy in danger? If he's ok should we get him a mate as he is only 6 months old.
Many thanks, Janet

Answer
Hi Janet,

I am very sorry to hear about your loss.  There is no way for me to know from here why exactly the boy passed, but since you lost another one early on, I am inclined to think there may be a hereditary issue at play.  Some genes can be passed from parent to offspring that causes them not to thrive, or to pass away at a very early age.  Typically this happens when the mice inherit the same deadly gene from both parents.  If this is the case, there is no way to know if the others inherited the same problem or not, but the older they get, the less likely there is a problem.  With this in mind, as long as the surviving boy appears healthy, there is no reason to expect he is in danger, although a vet visit to someone familiar with pocket pets like mice would certainly put your mind to rest and be sure nothing more serious is going on.

Yes, his belly may have contained blood if it appeared very dark, but that may not have been how he died.  When a mouse dies, the blood stops pumping around the body, and it will pool in the lowest areas.  This is just a natural part of death and may not mean he had something wrong with his belly when he passed away.

He does not need a mate - in fact, it's better if the surviving boy lives by himself.  At six months of age, he is more than old enough to produce offspring if paired with a female, and is also old enough to fight with any unfamiliar males.  Most boy mice prefer to live alone with just people for company, so if he will let you, it may be helpful to him to get a little extra love and attention from you as he grieves.

I am sorry once again that you and your daughter have had two losses with this litter.  I know it can be very hard, but sometimes it can happen with unplanned litters, as upsetting as it may be.  Best wishes to the rest of the babies and you all, and please let me know if there is anything else I can help you with!

-Tam