Elephant seals are the largest seals on the earth with two major species i.e. Southern seals and Northern seals. Size of a southern male elephant seal is about 6 meters (20 feet) long, and weight up to 6000 kilograms (8,800 pounds). The size of a northern male elephant seal is about 5 meters (16 feet) and weight is up to 3000 kilograms (6,600 pounds). On the other hand both northern and southern female elephant seals are smaller in size than their males, they are about 3 meters (9 feet) long and weigh up to 800 kilograms (1,764 pounds).

The average life span of southern elephant seals is about 20 to 22 years, whereas northern elephant seals just live up to 9 years. Northern seals are found in California while southern elephant seals are found in sub-Antarctic and Antarctica. They can survive in strictly cold environment, which has a great amount of fishes, squids and other sea foods for the seals.

Female elephant seals give birth to a single pup once in a year after 11 month pregnancy. The male elephant seals fight with each other for mating with females during breeding season. Sometimes these fights become more violent and they got injured badly. This is the main reason of extinction of this species. Another reason for their extinction is that they are unable to adapt themselves according to the changing environment which is why mortality rate is rising in this unique and the largest seal in the world.