Animal personality and behavioural syndromes have experienced rapid increase in interest in the last few years because of their possible role in the evolution of life histories. However, there is still a scarcity of studies concerning the mechanisms maintaining variation in behaviour as well as addressing their relationships to each other. In this paper, we tested the main assumptions of personality, focusing on the individual variability and repeatability of behaviour, and the identification of behavioural syndromes using the common vole (Microtus arvalis) as the species being studied. We also studied the effects of family group characters (group size, sex ratio and affinity to family) on the behaviour in this rodent. The animals were repeatedly tested in two behavioural experiments – novel environment (NE) test and radial-arm maze (RAM) test, from which seven personality traits were extracted. The study revealed that inter-individual variance in vole behaviour was consistent and repeatable. Individual-specific responses to NE corresponded with the performance in the maze, which revealed behavioural syndromes and possible trade-offs. Anxiety was determined by the size of the family group, whereas escape-related behaviours and maze-exploring tactic were more dependent on the affinity to the family. It seems that the development of personality traits we identified here is determined by the effects and structure of the family groups. Further studies are needed to confirm whether the observed variance in vole personalities is maintained by the fitness costs and benefits of the opposite tactics (here fast-random vs. slow-systematic exploration) in more natural circumstances.