Fur seal pups generally weigh about 5 - 12 lbs at birth and gain excessive amounts of blubber and weight through drinking its mother's milk which consists of marine oil, milk, and butter-like substances. They are about two feet long also.
1 pound
12-13 pounds
males weigh around 140 kg while females weigh 50 kg
The heaviest seal ever is the 4ton male elephant seal.
80 pounds