Introduction. The issues of typology are becoming increasingly significant in the context of expanding interethnic communicative ties, such as folklore, cultural, social ones, etc. Many fairy-tale plots, motifs – moving from one tradition, country to another, from people to people, developing more and more versions, changing their artistic appearances depending on new environments of their existence – retain their nuclear bases, which facilitates the formation of certain plot types. At the same time, these key elements do not function quite typically in fairy-tale traditions of different nations. Goals. The article contains a comparative study of motives for the expulsion of a hero who has broken with the past and taken up arms against his zoomorphic parent, but during the socialization faces certain difficulties that force him to leave the community. The paper analyzes twelve fairy-tale samples of Turko-Mongolic peoples with the typical plot ‘son of the bear’, determines the ‘reasons’ and ‘goals’ of exiling the hero from society, traces the essential variability, ‘inconstancy’, and ‘instability’ of motives as an element of the fairy tale plot. Methods. The work employs the structural-typological method of V. Propp, turns to key comparative research positions that make it possible to identify analogies and differences in various national traditions, uses certain techniques of the structural-semantic methodology developed by B. Kerbelite. Conclusions. The ‘inconstancy’, ‘fuzziness’, and variability of motives are manifested in details of the hero’s actions, reflecting the national specificity and confirming the law of ‘mobility’ of peripheral elements of the motif.