Introduction to harbor seals: Harbor seals inhabit the colder waters in and around the North Pacific. They have thick fur, rely on fat for warmth, and use flippers to swim. Harbor seals mainly eat fish, squid and crustaceans, and they can dive to waters below 300 meters in search of food. Harbor seals breed from February to May. The pups are white and furry. They nurse for 3-6 weeks, during which their weight increases exponentially.