Based on the results of a study conducted in 2006-2010 in the Buyunda River basin (a feeder of the Kolyma River), the influence of the population density of common shrews (Sorex) on some of the physiological and biochemical parameters (glycogen and lipids in the liver, the relative weight of the spleen, the white and brown adipose tissue cellularity of bone and brain tissue) was investigated. The content of energy reserve substances was correlated with the number of animals (fat deposits had a negative correlation; the glycogen content in the liver had a direct correlation). For the rest of the physiological-biochemical parameters, no significant correlation with the population density was detected, although for the content of brown fat and cellularity of bone marrow tissue in Sorex isodon, as well as the relative weight of the spleen in both species of shrews, a trend was observed. We suggest that the identified physiological changes indicate irregular feeding of animals in years with higher population densities.