Аннотация:The Middle Amur River region of Russia (between the rivers Zeya and Ussuri) shows a complex landscape structure, where a mosaic of boreal, nemoral, and steppe ecosystems is represented. The mammal fauna is also characterized by a mixture of various faunal elements and a significant spatial differentiation of their ratio. Changes in this ratio from prevalence of boreal species in the north-west to the dominance of nemoral species in the south-east is shown. Whole fauna includes 72 species of 6 orders.