To study the structure, heat-protective properties and moulting of the root vole and northern birch mouse

Based on the analysis of 18 dry collection skins of the root vole (Microtus Oeconomus) and 26 of the northern birch mouse as well as the corresponding observations in nature and in the laboratory, adaptive features in the structure and functioning of the coat, the microstructure of the hair shaft, as well as seasonal molts of these species were revealed. It was found, in particular, that in comparison with other small mammals, the root vole is distinguished by the thickest, tallest and most luxuriant coat. The structure of the hair core is also specific for root voles. Even in the widest part of the shield region, it is represented by only two rows of cells arranged very loosely and interspersed with large pigment grains and numerous air cavities. At the base of the hair and in the neck area, the core is single-row, and at the very tip is not expressed at all. The northern birch mouse, which prefers forest patches and clearings covered with dense grass and, the only one of all small animals that falls into hibernation, acquired in the course of evolution a rarer and coarser, but longer and less aligned than, for example, shrews and voles, a coat characterized by a three-layer. A rarer surface layer is formed by relatively thick and long guide hairs, the middle one is built of zonally colored guard hair and the lower one is made of thin and wavy down ones. The hair shaft, without forming constrictions of the core, thickens from the base to a well-defined shield region, and then passes into a thin thread-like tip. The shape of the core is spindle-shaped, without bends, longitudinal turns and constrictions, and the cortex layer in it does not change in thickness almost throughout the entire length of the core and consists of lentil-shaped cells arranged in rows. Individuals in a molting state are found throughout the summer. In adults who have overwintered, it takes place in June-July, and in newly-arrived - in August- September.