Fitness comparison of the European ground squirrel's populations living in different habitats and population density

Fitness in ground squirrels is a frequently discussed topic, reported in many publications, although it was rarely the subject of their study. The aim of this study was to determine which factors and find out how they affect the fitness of individuals, and thus the whole population of the European ground squirrel in Czech Republic. For this purpose we collected body mass data at three studied population, which are the main indicator of the fitness in ground squirrels. We also recorded information about injuries, reproduction status, ectoparasites and endoparasites. Moreover we collected all available data on the body mass of European ground squirrel in the central European region, and we compiled overview of body mass changes during the season. This enables us to compare our data with typical/common body mass value in particular sex, age and season. Recorded differences in body mass at three studied sites were related to sex, age, locality and season. We found positive correlation between the body mass and injuries from fights/reproduction activity in adult males. The relationship between body mass and reproduction activity of females was not found. Four species of ectoparasites, mostly occurring in adults, were recorded in studied populations. We also found five species of endoparasites, which..