The ice-breeding seals of the Arctic and Antarctic marine ecosystems occupy similar habitats in both land-fast ice and pack ice areas surrounding the continent. However, because the Antarctic is a continent surrounded by ocean, no terrestrial predators are present. In contrast, the Arctic is an ocean surrounded by continental land masses from which terrestrial predators have been able to access most adjacent sea ice areas. Consequently, the major predators in the Antarctic are marine while in the Arctic most, though not all, are terrestrial. This has resulted in the evolution of interesting differences in the ecology and behavior of seals in these two polar regions.