Middendorf (1869) raised the question of the main ways of adaptation of Siberian animals to the cold climate. He paid attention to the fact that northern mammals have thick and mossy fur, accumulate more fat for winter and have such a lifestyle that allows saving warmth in the body. Subsequent research has shown that the basis of the processes of adaptation of animals to the extreme conditions is made by the preservation of their energy balance in the process of interaction with the environment and preservation of relative stability of internal environment of the organism. Since the 1960s we have conducted research of adaptations of terrestrial vertebrate species to the cold climate conditions in the taiga and tundra zones of Yakutia. The main direction of our research is studying morphological–physiological and ecological parameters of the species securing the preservation of their energy balance in the harsh conditions of North-East Asia. The main objects of research are mass species of mammals, birds and amphibian. We have studied auto ecology, population ecology and ecological physiology of the model species. Special attention was paid to the ecological peculiarities of hibernating and large cold-adapted mammals: reindeer, elk, Yakut-horse, brown bear. It was found that during preparation to winter these organisms produce biologically active substances, which reduces the level of metabolism in winter, similar to those of hibernating species in the condition of hibernation. Economy of energy resources of widespread rodents is provided both by reducing the level of metabolism within the thermo-neutral zone and better development of physical thermoregulation of aboriginal forms, and, especially, by adaptive behavior. For mammals’ and birds’ ability to adapt to the cold, their morphological peculiarities of fur and feathers, composition of their lower limbs, anatomic peculiarities of nasal cavity and its blood supply are of great significance, also their adaptive behavior. The strategy of avoiding cold of two amphibian species of Yakutia – Siberian wood frog Rana amurensis and Asiatic salamander Salamandrella keyserlingii – is implemented differently: frogs winter in underwater pits lapsing into hypobiosis and salamanders find convenient wintering places on the land, sometimes far from reservoirs, i.e. frogs winter at around zero temperatures, whereas salamanders, who winter almost under a bedding, experience winter temperatures of the soil surface level to minus 30–32 °C. In these conditions the strategy of avoiding cold does not help and there has to be another strategy of cold (frost) tolerance, which can be secured by producing glycerol and other chemical agents in the organism. Crow birds feeding with more high-calorie food in winter sustain a high level of metabolism, whereas gallinaceous, whose food is less high-calorie, have to use a strategy of cold avoiding by keeping warm under snow shelters. Aboriginal forms of mammals (reindeer, Yakut-horse, musk-ox) are typical of lower level metabolism and body temperature in winter months. There are substantial differences in using tundra by the reindeer and musk-ox. The first one makes long migrations to winter pastures to forest tundra and summer tundra habitats, the musk-ox one has more settled lifestyle.
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Open Access
Jan 1, 2019
Alberto Sánchez-Vialas + 3
