The research, carried out over the course of about 50 years, aimed to highlight the factors that determine the ecological peculiarities of the vulnerable species Cricetus cricetus, elucidating the population parameters in different climatic and socio-economic conditions. The reduction of the C.cricetus population is conditioned by the changes in agriculture, with the increasing use of pesticides. As protective measures, the creation of protected areas, the cultivation of alfalfa in fields, the numerical regulation of predators serve.