[Effect of habitat type and population density on the stress level of midday gerbils (Meriones meridianus Pall.) in free-living populations].

New methods of noninvasive evaluation of the endocrine status of animals by the content of hormones in feces were used to study the relationship between the stress level and social (population density) and ecological (habitat integrity) indices in natural populations of midday gerbil in the Southern Kalmykia in 2000. Stress level proved to increase with habitat disturbance but did not depend on population density of animals. The obtained data are discussed in the context of species-specific ecology and social behavior of midday gerbils.