Atyasheva Tatyana N. RussiaTogliattiInstitute of Ecology of the Volga River Basin of RAS, Samara Federal Research Center of the Russian Academy of Sciences, 10 Komzina St., Togliatti 445003, Russiatatyana.atyasheva@mail.ru Author's articles Ontogenetic Changes in the Properties of the Poisonous Secretion of Vipera renardi (Reptilia: Viperidae)