OK... a clarification is needed I see!
I was not speaking figuratively.
There are actually four terms for how animals thermoregulate.
Ectothermic = an animal that gains needed heat from the environment
Endothermic = an animal that gains needed heat from physiological processes
Homeothermic = an animal that seeks to (needs to) maintain a constant body temperature.
Poikilothermic = an animal whose temperature naturally varies.
Adult mice are mostly endothermic and homeothermic. They are capable of keeping a constant body temperature by utilizing their own physiological processes. Only in extreme temperatures do they resort to insulated nests to prevent freezing.
Newborn mice are mostly ectothermic and homeothermic. In other words, they need a constant body temperature to remain healthy and alive, but they cannot maintain that constant temp by means of physiology - they must rely on the parent mouse, and an insulted nest to maintain the needed internal temperatures.
Remove those environmental factors, and the newborn mouse will die. The speed at which it dies will depend on the environmental temperatures to which it is exposed. That speed will also be hastened by lack of body mass, lack of body fat, and a physiological thermoregulation process that is not complete until the baby mouse is more mature.
One cannot be sure what the newborn mouse feels as it freezes, but the process LOOKS similar to that experienced by a reptile going into brumation. The heart and respiration gradually slow, the movements slow, and the newborn mouse appears to lack mental alertness as the temperature drops. There is no shivering, the squirming is not violent or frantic in appearance, and the processes of the mouse just slow down.
Due to lack of body mass, the newborn mouse does not last long when exposed to freezing temperatures, and the entire process is usually finished in a few minutes.
Quote:
Originally Posted by Cazador
Just to be clear, I think Kitkat was speaking figuratively since all mammals are warm blooded (endothermic). Small organisms have more surface area (skin) per unit of mass (volume), so they gain or lose heat more rapidly (like reptiles) than larger individuals do. Pinkies also lack hair and have minimal fat, so they have less insulation. This allows them to die and freeze quickly.
I won't offer an opinion on the most humane way to kill them because I think it's debatable and largely a matter of personal preference.
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