Harbor seals and northern fur seals belong to the pinniped family. Pinniped means fin or flipper-footed. Although these two types of seals share some similarities in structure, streamlined bodies, rounded heads, small tails, and flippered limbs, they have distinct differences, including their ears, coat thickness, and the shape and function of their front and rear flippers. The differences in the structure of their fins lead to a difference in the way they move, too. In this video, you can observe the difference in the way that harbor seals and northern fur seals move on land and in water.