the behavior and state of the majority of animals during the mating period. During this period the animals are restless, and the males frequently fight over females and utter special calling sounds (the bellow of reindeer, the moan of elk). In lands with sharply defined seasonal climatic features, the rut is confined to definite periods (for instance, in the forest zone of the USSR the rut of wolves occurs in January-February and that of Siberian stags and elks in September). In many tropical areas of the globe, rut occurs at various times of year, since mating periods are not limited to a definite season. Depending on weather conditions, availability of food, and the state of the animals, rutting periods may shift. Under especially unfavorable conditions the rut is poorly manifested. In certain domesticated animals (foxes, polar foxes) rutting periods are somewhat different from those of the same species living in the wild. Rutting periods also usually change when animals are transferred to another climate (for example, from the southern hemisphere to the northern).