The Common hamster,Cricetus cricetus,is spread throughout west and central Europe,Russia (eastwards to the Yenisey river) ,Northern Kazakhstan and North West China (Xingjian) .However,in the last 45 years its populations have declined markedly for no obvious reason.At the same time its abundance has increased in large Central and Eastern European cities such as Vienna,Lublin,Simferopol,Nalchik,etc.In an attempt to reveal factors enabling hamsters to adapt to the urban environment,we compared climate and habitat conditions in these cities.For these cities,the latitudes and climate are similar and these facilitate the propagation and growth of introduced plants such as chestnut,sycamore,plum,walnut,and gleditsia-all of which are high-quality food resources for the Common hamster.This species has established populations in city green areas such as parks,gardens down to embankments and buffer areas associated with communication lines.We contend that the Common hamster can colonize cities due to its higher resistance to stress,ecological opportunism,polyphagy and higher fertility compared to many other species.These features may be associated with their genetics and capacity for adaptation to novel evolutionary factors such as human impact.We assume that some native species with ecological pre-adaptations (like those of the Common hamster) can settle in cities of China,a country where urbanization is increasing apace.