The seasonal dynamics of the activity and the demographic structure of Carabus granulatus and C. glabratus populations was studied in the northern taiga of European Russia. The period of adult activity lasts for 90 days from early June to late August with the maximal activity observed in June. At the northern boundary of the range, the spring species Carabus granulatus retains its annual life cycle typical of this species in the other part of the range. At the same time, the reproductive period decreases, resulting in the synchronization of the development of specimens within the population. In the autumn species C. glabratus, a biennial life cycle with early summer reproduction is formed in the zone of broad-leaved forests of the northern taiga instead of the annual cycle. This species is characterized by the presence of two groups of individuals developing for two years each, but their development is shifted by a year. Such strategy results in the annual breeding of the species.