mice acting weird

Question
QUESTION: hi, i have 4 female mice divided in 2 cages..i bought the first 2 and after 2 weeks one of them one day seemed to be dead..i spent a few hours with her, i held her in my hands and for some reason after a little while she started acting normal..(i found her laying on the bedding with no sign of life..after she started moving again she didn't want to leave my hands)..unfortunately a week after that episode i found her dead..i went to the pet store to buy another mouse and i end up with 3 more..anyway, this thing happened with two other mice..except this time i found one the mice laying on the cage with half head missing..i read online, that mice could eat other mice if they're dead for the purpose of cleaning..my question is, why they have this behaviour? why they seem about to die and after a little while they go back to normal life, running and jumping? i noticed that if i try to wake them up sometimes they walk like they're drunk..i didn't have these mice for a long time (bought the first 2 just before xtmas)..i feed them daily, and every other day i put some seeds also..i change the bedding once a week..

ANSWER: Hi Dani,

That's strange, but without a vet it would be hard to guess at what is killing them.  Mice frequently bring home illnesses from the pet store (it's stressful to them, so they get sick more easily), so this could be causing them to get sick.  If one appears to be dead again but isn't, you might want to take a trip to the vet to see if it's something you need to give them medicine for.  Mice sleep in the daytime, but it sounds a little more serious than that.

Mice cannibalize each other for a few reasons, but if you are certain they passed away before being eaten then it may be a case of nutrition.  Mice eat mostly at night, and come back to their food frequently - the best way to feed them is not on a schedule, but to keep food present in the cage at all times.  Just refill it when it gets low.  Make sure the diet you are feeding them is formulated specifically for mice - other rodents have different dietary needs and this may leave your mice lacking in something specific.  Not only would this be bad on its own, but could keep them from getting over whatever is making them ill.

Best of luck!
-Tam

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

QUESTION: thanks for your answer..i have another question regarding my mice..now i'm left with 3 mice and 2 cages.i've read that mice get depressed if alone, and i need to know the best way to introduce the mouse in the cage where i have the other two..i tried to put the mouse straight in the cage but one of the mice went straight to attack her (and kept doing it every time i would try to separate them)so i had to remove the mouse, because it didn't look they were going to bond anytime soon..

thanks

Answer
Some mice just never get along, but you can help them settle in a bit by providing lots of cover for the new mouse to hide in, changing the bedding right beforehand, and making sure the cage has plenty of resources (extra food and water to reduce fighting over it).  Most females take a few days to get used to the new order in the cage when a new mouse has been introduced, but you should always separate if you see biting (actually grabbing the skin, not just chasing), boxing (standing on the hind legs and punching out at a chasing mouse), or excessive squeaking.  Some chasing and a small amount of squeaking is expected while they figure things out, but you should keep a very close eye on them any time you introduce them.  In extreme cases you can try dabbing a very small amount of REAL vanilla extract (never the imitation kind) on their chins and bottoms - this will make them all smell alike for a little while and may help them get used to each other.  Mice have very good noses though, so try this one last.

If nothing seems to work, don't push them.  Some mice never get along.  It's rare, but even in females, they may prefer to be by themselves!

-Tam