S. 2005. Diurnal activity patterns of coypu in an urban habitat. Acta Theriologica 50: 207-211.The ability of species to adapt to changing environmental conditions is a crucial need for surviving in human influenced landscapes. Especially non-indigenous species, which are flexible in their behaviour, may successfully enter and establish in new habitats. We compared the activity patterns of the invasive coypu Myocastor coypus (Molina, 1782) in an urban habitat in Germany with patterns observed in its native distribution range in South America as well as in areas, where it was introduced. In summer 1998 and winter 1999 a radio tracking study was carried out on six adult coypus, supplemented by count data on untagged animals. Whereas main activity in non-urban populations was recorded at night including dusk and dawn, coypus in the urban habitat were active during the day and early evening. We never observed animals between midnight and dawn. This reversal of activity patterns is attributable to deposition of human food in the city area during the daytime.