In addition to using sonar for navigation and locating groups of food, its believed seals use their whiskers as a form of radar. The whiskers detect movement in the water and allow the seal to zoom in a particular object. Through the use of their sonar and radar, seals can actually find food in complete darkness better than in the light. When in the water, a seal's nose closes automatically and doesn't reopen until it surface. This also is true of when they're sleep.
Seals sleep just under the surface of the ocean and can resurface for air without waking.
Unlike other seals found in Antarctica, Fur Seals are not true seals. They are from the eared seal family. Although extremely sociable among other Fur Seals, they are known to bit humans without provocation and move well enough to outrun humans on land. These poor manners were not helped by the fact that Fur Seals were heavily hunted during the 19th century. At one point, their total population was reduced to a few thousand.