The average weight of an adult seal depends on the seal species; for example, Atlantic harbor seals weigh an average of 150 to 300 pounds. Female elephant seals have an average weight of 900 to 1,800 pounds, and male elephant seals average approximately 3,000 to 5,000 pounds, but can weigh as much as 8,800 pounds. Seals live throughout the world's various oceans and seas regardless of the temperature.
Males often have the most variable weights and lengths, also tending to weigh more than females. Seals gain their weight and grow from a developmental standpoint by eating a diet composed of mainly fish and squid. They live anywhere from 9 to 25 years in the wild, depending on the species.