As you may know, we pinnipeds are adapted for an aquatic environment and are most vulnerable to predators out of the water. For us, sea ice is the safest ground with minimum risks. From there we like to dive down to the continental shelf where we feed . The farther the ice edge recedes from the continental shelf in the summer and the longer that lasts, the farther we have to travel to eat. Some scientists believe that the sea ice edge could be receding because of gradual global warming.