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Darwinism and HEAT

Sasheena
06-06-2005, 11:33 PM
Well I thought I might ramble on a bit about my mice, about darwinism, and a few other topics. :)

Let's roll back the clock to the first year I started raising mice. Late summer, AC failure, and 3/4ths of my mice died along with nearly all of the males. I cried buckets. (they all had names!)

Early spring the following year, I switched feed, AND there was a heat wave, AC worked but was overworked and not keeping up, half my mice died.

Late summer same year, the MAIN AC died, and Wumph! a third of the mice are dead.

Roll forward again to the next spring, heat started up again, AC working fine, but still, 1/4th of the mice die within a week of the temperatures really going up.

End of the summer, AC cord (new AC) chewed through by the rats.... about 15% of the mice killed in the heat. (The RATS were fine)

Now here we are at the beginning of a new summer. Power failure, and my NEW AC is so clever... it needs to be turned back on manually after the power goes out. Of course I don't know this (silly me) and after a day and a half, the smell is pretty powerful.... I go in and about 5% of the mice are dead.

See a strange pattern developing? Or several?

1. Raising mice in Arizona is the pits during the summer, 1 little AC failure, and you have problems!

2. The number of casualties I've had has decreased dramatically every year.

This second point is really the point of this post.... I have some thoughts about "survival of the fittest"...

When I began my colonies, I had some lab mice, and a LOT of fancies. Very little tolerance to the heat. After the first die-off, all the mice remaining were the most hardy mice... the ones who could tolerate heat the best. Over a number of different die-offs the only mice that go on to reproduce in my colonies are the ones that have the strongest resistance to the heat. Also, in the last year and a half we've lived where I've been unable to keep the wild house mice from infiltrating my tame colonies. (They chew their way INTO my mouse cages, they run on several mouse wheels i have set up for them, they have litters in the middle of the mouse house floor!) I estimate that approximately 20% of my mice are hybrids with the wild mice. This makes them slightly smaller, a lot more athletic, and I'm sure that with the influx of wild Arizona mouse genes comes a high level of tolerance to the heat.

Some of the drawbacks to the heat... the mice still don't produce much when it's so hot. I noticed a different trend while cleaning and clearing up the mess from today's tragedy.... as before, the highest number of casualties were among my pregnant females about to pop. But instead of ALL of them dying, I think that I had about 25% of the very pregnant end up having MISCARRIAGES and LIVE through the experience. I found a number of "aborted" litters. I found that interesting that several of the mice were able to cope with the heat in this way.

Of course I have to hope that I have no more AC incidents, but it seems that ACs are just NOT the most reliable thing here in AZ.

Anyway, I thought I would share some observations.

TripleMoonsExotic
06-07-2005, 12:37 AM
Sorry to hear about the AC problems you've had! I'm going to pick up a small AC for my rodent room this weekend. It's getting pretty hot/humid and I think the smell is WORSE when it's warmer out. I'm also worried about their reproduction!

Thanks for the info!

peep_827
06-07-2005, 08:14 AM
Wow, that is quite a little evolutionary experiment you've got going there with your mice! Interesting results, to say the least. Maybe eventually you'll come out with a heat-resistant strain of feeder mice to market in your area? LOL

Jynx
06-07-2005, 10:29 AM
oh do I know how you feel. At least out in buckeye you get a little more fresh air than here. I had to go pick up live feeders the other day for one of my adults who, for some reason, just thinks that the same frozen mice he's been eating forever just aren't good enough. I head all of 3 miles down the street to pick some up. Car sits in the sun for about 5 minutes. Get in the car, turn AC on full blast. Takes about 5 minutes to get home. Lookin in the bag and the mice are pretty much paralyzed. Grrr...So I spend the next 2 hours running these poor mice under cold water trying to cool them off...anything. In the end they all died, which SO defeats the purpose of buying them in the first place!!!

Sasheena
06-07-2005, 07:53 PM
Yup, I know how that is. Key is to have the car well-AC'd before you bring the critters out.... and best thing of all is to get a big bag of frozen peas, a couple of frozen water bottles.... use the frozen peas as substrate, put the water bottles either inside or outside the container... the mice will eat the frozen peas and/or lounge around the substrate and that should work for getting them from point A to point B. :) If you ever need some "heat resistant" mice... well Buckeye's not THAT far away. :)

Overall this latest issue resulted in very little loss to my colonies. I have 30 small cages, a 'boy-weaner' bin and a 'girl-weaner' bin, plus one large 20 gallon for my "experiment" .... 1 male and 10 or so black-eyed-white mice.

In the summer I'm hard pressed to keep the mice self-sustaining. Knowing this from "bitter experience", this year I stepped up production in January, freezing in order to keep the mouse population at least semi-contained. So at the moment I probably have enough critters in the freezer to get me through the worst of the bad weather. The mice will probably have just enough babies to feed the hatchlings that require live, and a few of my snakes that won't eat frozen, and also to replenish themselves. Come fall, I'll have to cut back on the colonies to keep from having them overrun the mouse house.