Abstract <p>The composition and content of fatty acids of the sand lizard (<i>Lacerta agilis</i>) and its potential food objects in the shore and steppe biotopes were studied. For the first time, it was established that the content of long-chain omega-3 polyunsaturated fatty acids, primarily eicosapentaenoic acid (EPA), significantly increases in the tissues of lizards from a shore biotope during the period of emergence of amphibious insects from the nearby saline Lake Shira. Among all the food sources of lizards, the highest EPA content was found in chironomid imago. The content of docosahexaenoic acid (DHA) in the muscles of the lizards was also high, although this acid was not detected in the invertebrates that the lizards consumed. In this regard, it was assumed that the sand lizard is able to biosynthesize DHA from biochemical precursors contained in food.</p>