# Physiological changes in mus mus



## moustress (Sep 25, 2009)

I've irritated a few folks with what night have seemed like off-hand remarks about keeping fancy meeces at lower temperatures, and speculated about the differences between larger 'show type' meeces and 'pet type' mousies.

I was serious about wanting to know more about show meeces, and I've been thinking about it quite a bit. The other night I was ruminating about my mousies in general, and remembered something that I learned years ago in Physical Anthropology. It has been found that physiological changes in humans are induced by the environment in a single generation in Aleut tribal peoples, and in various tribes in the Andean mountains.

In the case of the Aleuts, it was found that adults retained a type of fat cell that all newborns are born with, and usually lose after the first few months of life. Commonly called brown fat cells, they burn calories at a prodigious rate, generating body heat that makes it easier for an infant to maintain normal body temperature. In the Aleuts, it is found that these 'brown fat' cells retain form and function through out the life of the individual. I think you can see where I'm going with this; size is easy enough to explain away as simple selection over many decades, but the ability to tolerate colder temperatures is not, to my mind, as easy to explain.

So my question is this: do meeces have this type of fat cell either when born and/or later in life. Could it be what makes the difference?


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## SarahC (Oct 3, 2008)

I can't find the bit where you allegedly irritated people and have no knowledge on such a scientific question about fat cells.All my mice are out in the shed with no heating even the hairless.I don't find it a problem.Do you?


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## moustress (Sep 25, 2009)

Yes, I've noticed that my some of my mousies look stressed out, with dull coat and hunched posture, when accidentally exposed to temps lower than 60F for more than a fraction of an hour. I most certainly understand that many English mouse keepers use unheated areas to house their meeces, and that the critters seem to tolerate it quite well (up to a point).


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## Rhasputin (Feb 21, 2010)

I wonder if that's why eskimos and inuit peoples always have that 'baby fat' look to them when they're young adults? o:

Fascinating stuff.

My mice seem un-effected by colder temps, but heat exposure really bums them out.


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## Megzilla (Oct 12, 2009)

My mice are in the shed, and they're still happy and running about in winter I do have to give them extra bedding though  but they don't like the heat much.


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## SarahC (Oct 3, 2008)

I don't clean the warm nest area out in very cold weather.


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## CatWoman (Jun 19, 2010)

moustress said:


> So my question is this: do meeces have this type of fat cell either when born and/or later in life.


Yes, they do.

http://www.vivo.colostate.edu/hbooks/pa ... wnfat.html



> A good place to observe brown fat is in mice, where it persists into adulthood. Dissection of a mouse will reveal two large, lobulated masses of brown fat on the dorsal aspect of the thorax, between the scapulae. Masses of brown fat are also to be found around the aorta and in the hilus of the kidney.


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## moustress (Sep 25, 2009)

Thank you! Then my follow up question would be whether brown fatty deposits are depleted when exposed to cold and then can they be restored or regenerated after that. I'll go back and reread this and check out the references after I've had my second cup of coffee.


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