Cages are good, but usually only if you have a way to blow cool air through
them (such as by a fan). The risk is that the draft will make them sneezy
and sick, but that's treatable and not always life-threatening, so in the
middle of summer, I usually take the risk.
Glass fish tanks are just as good as cages - as glass has a tendency to stay
cool (it loses heat very quickly - which is why if you have lots of windows
in your house it can get very cold in winter without a constant source of
heat). A friend of mine discovered that sometimes what you use for bedding
makes a difference. The lucerne pellets (that cat litter made from grass)
can actually generate its own heat if left in there long enough. Not good
for summer. Either way, we found that the ones who survived the heatwave
were the ones who buried themselves in their litter, or dug a clear space on
the floor to lie (keep in mind that wild mice survive by burrowing into the
ground). You need bedding, but something other than lucerne.
Also, the closer they are to the floor, the better off they'll be. The
hottest place in any house is near the ceiling, and we lost most of the ones
who were at table height or above. Any on the floor or below table height
were generally okay. It may only be a couple of degrees difference, but
that's sometimes all it takes (and thus why it happens so quick).
Ice packs work well. In extreme heat they snuggle up to them, but otherwise
putting them in a position where they cool down the whole cage is good. I
save them for emergencies usually (and very hot days). There is no
sure-fire method of keeping mice cool, but we've tried a lot of things. A
shallow dish of water is a good idea. A couple of other mice that survived
our heatwave had sat in their water dish to wait it out. I plan to get a
large, shallow 'bath' for the big tank in summer, just so they have
somewhere to go and cool down if they need to.
If you have a blistering hot day, and find your mice are (in extreme
conditions) close to death because of it, I have known people who hold them
in the freezer for a few minutes to lower the body temperature. It saved a
few. Since mice can't effectively lower their body temperature, it's the
most important thing to do - run them under cold water taps, sit them on ice
packs. Put frozen bottles of water in the cage. Anything to help them get
cooler. I think I have one who is partially brain damaged (but otherwise
okay) from the heat. It happened so quick - there was no warning (at least
nothing we could recognise back then). We know better now.
Hope this has helped. You'll probably find they'll be okay in the tank.
Give them a frozen water bottle in the cage when you go out, and another one
against the cage outside (to cool the surface of the glass down). A dish of
water in it, and a circulating fan - they should be okay. If you're worried
it might be too cold, then wrap the frozen pack in a hand towel. it will
still cool the air down. Put them on the floor (in the bathroom is good -
tiles/linoleum or whatever are always cooler than carpet).
> Question for Joch - what should we do when it gets too hot? If you put
> a pan of water in the cage, will the mice get into it to cool down? I
> read someplace to use an ice pack, but that wouldn't be effective in a
> wire cage unless the mice would snuggle up to it. Also, if I was away
> at work I would need something to keep them cool for 8-9 hours. I don't
> have air conditioning, and it can get to 90-100 degrees in my apartment
> even if I leave the windows open. A fan might help, but my mice are in
> an aquarium so the air won't blow directly on them.