Terrestrial Mammals in Cold

Abstract

Terrestrial mammals in temperate, subarctic, and arctic environments must adapt to cold in order to survive winter. At high latitudes winter may last for 8 months and mammals may be exposed to extreme air and ground surface temperatures of −50°C. Similar conditions may exist at high altitudes in temperate regions. In deserts during winter, subfreezing temperatures are common at night. At temperate and arctic latitudes it is not unusual to find a small vole (20 g) and large moose (400 kg) occupying the same habitat. Both of these mammals maintain relatively constant high body core temperatures and remain active throughout the winter (i.e., they do not exhibit torpor or hibernation). This is remarkable since body size influences the level of heat production at thermoneutrality, the inherent insulative and metabolic capabilities for combating cold, and the nature of behavioral responses. As a result, the solutions employed by small mammals for adapting to seasonal cold may be different than those used by large mammals. In addition to making seasonal adjustments, mammals that reside in cold-dominated regions such as the arctic may show climatic adaptations which distinguish them from mammals at lower latitudes.