Marcel is an associate professor at the Department of Zoology, P. J. Šafárik University in Košice, Slovakia, where he teaches courses in vertebrate zoology, mammalian, ecosystem, and urban ecology. He specializes in the study of the distribution and ecology of amphibians, reptiles, birds, and mammals, with a special emphasis on bats. For almost fifteen years, he worked as a professional nature conservationist. He has authored or co-authored more than 500 publications and he has conducted field work in many countries in the Balkans, Middle East, Asia, and Africa, e.g. Iran, Syria, Libya, Mauritania, and Namibia. Marcel is an amateur photographer and his first solo exhibition was held in 2019 in Revúca, Slovakia.