Found in coastal regions of the North Atlantic, Arctic, and North Pacific Oceans; also the Mediterranean and Black Sea regions. They are found in bays, estuaries, river mouths, and sometimes ascend further up rivers.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); arctic ocean (Native ); atlantic ocean (Native ); pacific ocean (Native ); mediterranean sea (Native )
Other Geographic Terms: holarctic
- Dollinger (editor), P. 1988. Convention on International Trade in Endangered Species of Wild Fauna and Flora; Identification Manual Vol I. Mammalia. Switzerland: Secretariat of the Convention.
- Nowak, R. 1999. Walker's Mammals of the World, 6th Ed. Vol II. Baltimore: John Hopkins University Press.