Abstract:In semiarid regions like the Brazilian Caatinga, the long dry season suggests that it is a homogeneous environment. However, differences in climate, soil, relief, and duration of the dry season across this biome has prompted the division of Caatinga in eight ecoregions. Here, we test the validity of these ecoregions for bats, which play a fundamental role in the balance of ecosystems. A literature review was carried out to investigate the distribution of bat species in all Caatinga ecoregions, and the lack of sampling efforts. In total, 90 chiropteran species were recorded in the biome. Bat distribution is not homogeneous, and almost all ecoregions present exclusive species. Gaps in chiropteran sampling efforts occur in all ecoregions. A robust and significant correlation was observed between the number of studies reporting samples and bat richness of each ecoregion, indicating that more research will increase recorded richness in these areas, and in the Caatinga as a whole. The existence of at least four ecoregions in the Caatinga was also supported. This underlines the importance of these areas to conservation initiatives.