2 new mothers - 1 eating babies

Question
QUESTION: I have 3 female mice & 1 male and it's been years since I've owned mice as pets. Two females gave birth in the last 24 hours & I've since separated the male. The females are nested under some Kleenex I added so I have no idea how many are there. One mother was nervously carrying a pup around the 2 joined cages and I'm fairly certain I saw her eating it a few minutes later. Why did she do this? I think I see another dead pup or part of one. Should I leave it there? The mice get nervous when I hover over the cage, even to peek in. Out of excitement about the two litters, I stood next to the cage a few times to observe them and I think that was a huge mistake on my part. I didn't open the cage or touch anything but my presence may have done more harm than good. Did she eat them because of my presence? What should I do? I feel horrible that this happened and lost on what to do. I'd appreciate any advice or info about their behavior. Thanks.

Jenny

ANSWER: Dear Jenny,

There are several reasons for a mother mouse to eat her babies, one simply being because it is her first litter.  She may also do so if she gets stressed-- feels it is not a safe place to raise babies; or if there is something wrong with the pup. Then again, there are mice who are simply not good mothers. I would not worry about a couple of dead babies (yes, remove the part if you can do so without upsetting them), because there may be something wrong with them. But if it really seems like she is going to eat her litter (let's say you witness another three), take her out and let the other mom nurse all the babies-- I hope the total of babies is 16 or less.  If the second mother ends up raising them all, give her a good 4 weeks after they mature to breed her again, to get her strength back!

As for breeding the first mouse again, the question is why she ate them, which you can't really know. If it was because there was something wrong with them, it means she carries a defective gene of some sort and you don't want to breed her again. If it was because she isn't going to be a good mother, well, that's the answer. If it was because she felt stressed, then she is too high-strung to be bred. However, if it was because she was confused as a first time mother, she would be OK to breed. So it is up to you. Certainly if you breed her again and see her eat even one pup then you must never breed her again.

I hope none of this is relevant because you simply don't see the behavior again at all.  Keep me posted.

squeaks,

Natasha

---------- FOLLOW-UP ----------

QUESTION: Thanks Natasha,

The nest is on the second level of a cage and the door to the 2nd level is on top, so if I open it to remove the dead pups I'll only be inches from the nest. I just got the mice after Christmas so I haven't had them long enough to socialize with them. They still run from me.

The two mothers created a mixed nest so I have no idea how many there are and if the nervous mother killed anymore, especially with the Kleenex piled on top. When I saw the 1st litter, I saw at least 6. When I saw the 2nd mother giving birth, she only had two with her, but I don't know if they were the first two, the last two or the only two. While she was giving birth, the 1st mother carried the pups away and put them with her nest creating one big nest of pups. At one point, all three females were all cuddled together with the mixed nest and I saw the nervous mother nursing. She seemed fine then. It was hours later when I saw the dead pup and her killing the other one. She even seemed like the more laid back mouse whenever I was feeding them or changing the water. The most nervous female seems to be the better mother, more attentive (so far, crossing fingers). Their behavior just seems backwards. If a mother sees another mother killing her pups, is there a chance that the better mother won't let the bad mother near the pups even if some aren't hers?

Jenny

Answer
Dear Jenny,

If you are worried that you might disturb them, leave them alone. A dead pup can't make too much of a mess. If there are three moms and you see any more problems, take the mom out. It is good that they all share a nest- they spell each other and it makes it much easier for all involved. I wouldn't suggest breeding all three at the same time again, though. You don't want more than two litters in a cage.

I don't think the mice could be sophisticated enough for the good mom to realize the other is a bad mom, especially since there wasn't a lot of carnage.

I hope everything works out.

Squeaks,

Natasha