The Harbour seal is considered the most successful pinniped species in terms of the breadth of niches it can occupy. They are widely distributed, encompassing coastal areas of the Pacific and Atlantic oceans in the Northern hemisphere. In the North Sea, Harbour seals are regarded as sentinel species because the health of their population is seen to reflect the health of the marine ecosystem generally. Taking advantage of a unique sample of P. vitulina from the German Northern Sea, the Böhmer research group comprehensively investigates aspects of the seal’s anatomy, morphology, ontogeny and evolution in selveral ongoing projects.