Materials to monitoring of amphibians populations age structure in the urbanized territories of the Volga basin

Date on age structure of two city population of a lake frog Pelophylax ridibundus (Pallas, 1771) are provided in work. Definition of age was carried out by a skeletohronologiya method. It is shown that in both populations the sexual maturity comes at the age of two-year. The maximum life expectancy is 6 years. The main part of populations is presented by individuals of 2-3 years age.