Maintenance of Arctic Populations of Mammals

摘要: Seals roaming freely over the oceans are difficult to observe and obscure in their ways. At season of breeding, however, they resort firm ice or shores for periods explicit each population become attached specific breeding localities until pups acquire sufficient capability independent aquatic life. In these temporarily fixed situations populations visible. Exposure at time particularly by that congregate numbers, has favored human exploitation leading near-extinction some populations. The tenacity traditional attachments is shown persistent exploitation. On Pribilof Islands hauling out fur seals (Callorhinus ursinus) established rookeries worn hard rock smooth. southern coasts smoothly rocks attest ancient places were long utilized now extinct. Erosion rocky demonstrates persistence seasonal use. Northern elephant (Mirounga angustirostris) a northern outpost (Arctoce-phalus phillippii townsendi) have reconstituted from most only few survivors slaughter occupy again beaches used predecessors off western Mexico California.