Hypothermia and Hyperthermia

Although mice are highly adaptable to living in different climates, they are inefficiently homeothermic and cannot tolerate sudden and extreme changes in environmental temperature. In a stabile environment, core body temperature will normally fluctuate several degrees in a day, depending upon activity. Hypothermia and hyperthermia are all too common occurrences dur­ing shipping, when crates are moved from one environ­ment to another. Water bottle accidents cause high mortality within a cage from hypothermia. All of these factors can result in high mortality with few, if any, discernible lesions. As in dehydration, massive lympho­cytic apoptosis in the thymus is a hallmark lesion.