Rhinolophus euryale is originally cave dwelling bat species reaches the northern border of its area in central Europe (Slovakia and Hungary). However, there is a major change in roost preference in summer observed in this region; the species started to use lofts and roofs since the 70's of the 20th century in Slovakia and Hungary as the result of the synanthropisation process. We analysed database of faunistic records on Rhinolophus euryale (more than 1500 data items) from Slovakian, Hungarian and Romanian range of the species covering period 1878–2012. We evaluated changes at the sites (both, winter and summer roosts) where long term data were available. We analysed data on temperature from eight R. euryale roosts (6 attics and 2 caves) for one year period. The year-round average differences between two roost types are 4.6 °C. Daily temperature amplitude in cave roosts were only 1.5 °C, but in attics roost were 8.4 °C. Thus, caves roosts are relatively stable comparing to attic roosts. We hypothesised that these facts must have impact on species ecology and probably in biological adaptations. There should be differences in active social thermoregulation, immunological characteristics, or other anatomical attributes. Preliminary results showed that there is significant difference in forearm length within the females roosting in caves and females from attics. More research effort in this topic is necessary.