Authors: Bernátková, Anna; Oyunsaikhan, Ganbaatar;Šimek, Jaroslav;Komárková, Martina;Arenas-Castro, Salvador ;Sillero, Neftalí ;Bobek, Miroslav;Ceacero, Francisco;

Reintroduction is one of the most effective conservation techniques, but the risk of failure is high since the animals must adapt to a harsh novel environment. Przewalski's horse, once listed as Extinct in the Wild, is one of the best examples of successful reintroduction since 1992 (Gobi B). The current population, around 350 individuals, involves wild-born, long-term and newly reintroduced individuals. By direct observation of selected harems, we studied the effect of the origin (wild-born vs reintroduced) on the response to environmental conditions, social network and habitat use at harem and individual levels. Significant influence of the origin was found for all these categories. Compared to long-term reintroduced harems/individuals, wild-born groups showed clearer ethograms, well adapted to the changing weather conditions, complex social networks, and selection of habitats with higher NDVI values. Newly reintroduced groups (during soft release) showed the less complex patterns. The results confirm a slow behavioural adaptation of the horses to a new environment, probably not total until the second generation comes. These results may assist future reintroduction programs and the successful conservation of the species. Future research may focus on captive breeding conditions and their effects on subsequent adaptation to reintroduction at the individual level.