Among the representatives of the subfamily Arvicolinae the interspecific differences (Clethrionomys glareolus, Clethrionomys rutilus, and Craseomys rufocanus) in the respiratory capacity of red blood and the immune status are presented in conjunction with the basal metabolic rate, the level of sociality and eurybionism, and thermoregulatory function. The degree of differentiation of voles in terms of haematological parameters has corresponded to the level of phylogenetic relationships between species. Correct conduct of interspecific comparisons of haematological parameters of voles is possible only within the same reproductive-age groups.