The European Hamster (Cricetus cricetus), also known as the Eurasian hamster, black-bellied hamster or common hamster, is a small rodent native to Eurasia. The European hamster is a nocturnal or crepuscular species and it lives in a complex burrow system. It eats seeds, legumes, root vegetables, grasses and insects. It transports its food in its elastic cheek pouches to the food storage chambers. These may be quite large and may consist of a total of 65 kg of food including 5 kg of potatoes and 15 kg of grain. It hibernates between October and March. During this time, it wakes every five to seven days to feed from the storage chambers. The adults reach sexual maturity when they are about 43 days old and breed from early April to August. The gestation period is 18–20 days and the size of the litter ranges from three to 15 young, which are weaned when aged three weeks. They are usually solitary animals.
In 2020, the European hamster was classified as critically endangered across its global range by the IUCN Red List. Although the reasons for its drastic decline are not fully understood, it has been linked especially to habitat loss (for example due to intensive agricultural practices and the building of roads that fragment populations), but also pollution (even light pollution appears to significantly reduce local populations, unless counterbalanced by other factors), climate change and the historical fur trapping.