Their number and species diversity is determined by the higher-lying areas, usually surrounded and secured by water.

Among the mammals in the Danube Delta ecosystem, we can enumerate the following types: otter (Lutra lutra), mink (Mustela lutreola), small ermine (Mustela nivalis), wild boar (Sus scrofa), Fuchs (Canis vulpes), wild cats (Felis silvestris) and hare (Lepus europeus).

Recently the Enot dog (Nyctereutes of procynoides) is emigrated and also easily adapted.

We know still the Bizamratte (Ondrata zibethica), more rarely Nutria (Myocastor coypus), mention and many more.