Mechanisms of heat conservation in the litters of mice ( Mus musculus L.)

Abstract o 1. The importance of huddling, parental brooding and nest material as insulative mechanisms in the litters of mice was investigated at 25°C. 2. Huddling unexpectedly elevated oxygen consumption rates in the youngest litters, when a comparison was made with the oxygen consumption of isolated mice of the same weight and age, probably because it encouraged a high level of activity. 3. In older litters huddling depressed oxygen consumption even in mice close to weaning. 4. At all stages of litter growth nesting material insulation and parental brooding depressed oxygen consumption. However, in large litters of mice, close to independence, the oxygen consumption was not depressed to the same extent as in smaller and younger litters, possibly reflecting an attempt to eliminate hyperthermia.