Содержание воды в тканях двух видов бурых лягушек после водной и наземной зимовки

Amphibians have high water content in the body (77-83 %) and are resistant to its strong fluctuations in both diurnal and seasonal aspects. They have evolved numerous physiological mechanisms and behavioral responses to cope with the loss or excess of water in tissues. The authors assess the water content in the liver and skeletal muscles as well as the relative mass of liquid in external lymphatic sinuses of two brown frog species, Rana temporaria and R. arvalis, living sympatrically but differing in their attitude to water: the degree of attachment to water bodies and humid places, the stereotype of wintering, and the character of daily activity. It was shown that in the water-loving and waterwintering common frog, the water content in tissues is high in spring (79-80 % on average) and does not differ between females and males. In the moor frog, populating drier habitats and wintering on land in the frozen state, water content in skeletal muscles of females and males was comparable to that of the common frog (80-81 %), but in the liver it was significantly lower (74-75 %). The revealed regularity was also preserved while assessing the relative mass of subcutaneous lymphatic fluid: it was several times greater in the water-loving common frog (3-11 %) than in the moor frog (1-5 %). Thus, although the general principles of water metabolism in amphibians are similar, there are some physiological features of water uptake and extraction in specific species.