The Harbour Porpoise is a small whale, living in shallow coastal waters of the northern hemisphere, feeding mostly on fish. It can be found along the Baltic Sea coast from Poland to Fehmarn Island. Examining its inner organs, the Greek philosopher Aristoteles found similarities to mammals. So the nickname 'sea pig'and the German name 'Schweinswal' developed. The Baltic Sea population is endangered by pollution, bycatches because of intensive fishery, and noise exposure.
Image: Friedrich Specht, Brehms Tierleben, public domain