In Trans-Baikal, East Siberia, a large body of rock art is related to the early nomadic cultures of the 2nd-1st Millennia BC. Rock art traditions present there have been considered as homogeneous and persistent during this long period of time. This paper aims to explore the manifold nature of these traditions related to turbulent social and ethno-cultural processes that occurred in the Steppes of Eurasia. The paper is specifically focused on the Selenga rock art tradition and the Kyakhta petroglyphic group which are better defined in time and space through the analysis of styles and motifs. This research is based on data collected by the author during extensive fieldwork in Trans-Baikal in 2017. Several waves of foreign influences were distinguished in the rock art implying that the history was more complicated then as seen from archaeological record available today. Such intense cross-cultural relationship could have influenced the evolution of ethno-cultural identities the phenomenon of which may explain the emergence of some motifs which were not brought by newcomers but developed locally as a response to a threat to social and cultural continuity.