Ireneusz Ruczyński is an Associate Professor at the Mammal Research Institute, Polish Academy of Science in Białowieża, Poland. His main research interests include the ecology, behaviour and physiology of bats. He conducted studies on roosting behaviour and learning process. In his work he combines field (e.g. radiotracking and acoustic methods) and laboratory methods (observation of bats in captivity, manipulation of environmental conditions, measurement of metabolic rate and sperm quality). He is also interested in processes which lead to sociality in males. His research group works on testing whether energetic restrictions can lead to sociality in male bats and how being social may affect the bats’ reproductive capabilities in turn. Recently, he started studying role of bats in transferring organic material from aquatic to terrestrial ecosystem.