Winter acclimatization and survival of wild House mice

If an animal is physiologically adapted to its environment, it is more likely to survive than if it is not. The relation between physiology and survival in the wild has been studied in an island population of the House mouse ( Mus musculus L.) during two winters. Multiple regression analyses showed that significant information on survival was obtained from several measures of cold acclimatization (e.g. metabolism within thermoneutrality, metabolism under cold stress, and haematocrit), though little came from a measure of non‐shivering thermogenesis (noradrenaline sensitivity). The predictive value of the multiple regression calculated in any one year was low when applied to another, though similarities in the physiology of survival were present. The survival of a mouse will result from the interaction of many facets of its biology with its environment: in nature it is rare for either of these to remain constant from year to year.