Kuznetsova Ekaterina V. RussiaMoscowAvtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution “Petrovsky National Research Centre of Surgery”, 3 Tsyurupy St., Moscow 117418, Russiakuznetsovaekvl@gmail.com Author's articles Seasonal dynamics of sex hormone levels in Elaphe dione (Pallas 1773) (Colubridae, Reptilia) in the northern part of the range