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The southern elephant seal is considered one of the two species of elephant seals—the northern elephant seal and the southern elephant seal. Considered the largest member of the Carnivora order to have ever lived, its name is derived from its huge size and the male's large inflatable elephant-like proboscis on its nose—capable of making extremely loud roaring noises during their mating seasons.  Much larger than the northern elephant seals, the males weigh about 8,000-pounds as compared to the 1,500-pound females. The bulls usually do not reach sexual maturity until 3 to 6 years of age, but most do not breed until 10 years of age.  One bull shot in South Georgia was documented as weighing 11,000-pounds and 22.5-feet long.  

DIVING CAPABILITIES

The eyes of the southern elephant seal are extremely beneficial in capturing its prey. Large, round and black, the eyes have a very high concentration of low-light pigments with a high width. The prey they hunt are squid and fish, diving repeatedly over twenty-minutes to search for them. The longest recorded dive was almost two hours in duration over 1400m in depth. The southern elephant seal is the best performing seal regarding its sequence of dives, duration and depth resulting from non-standard physiological adaptations, common to marine mammals but particularly in elephant seals.

How they coped was based on two different types of diving strategies: its increase in the storage of oxygen and reduce consumption. And previous studies have shown that there is a strong, significant relationship between the duration of the southern elephant seals' dives and the time of day/week of the year when they were performed, but the depth of the deepest dive had less significance with the local time of day and season. It was found that dives occurring in the morning were the longest, while the evenings had shorter dives. Midday had much deeper dives while midnight had shallow dives.  The dive duration increase from autumn/spring as compared to winter was 11.5 to 30.0 minutes.

Typically the southern elephant seals spent approximately 90% of their time at sea—diving from about 300 to 600m to depths of 1500m. The larger males had slightly less of a dive duration which was females/25.2 minutes as compared to males 24.1 minutes. The study also showed that feeding changes had greater duration when the seals fed in the open ocean as compared to foraging on the continental shelf, with both physiological and ecological constraints weighing heavily on the seal's dive duration.

FOOD SOURCES

When they find food sources at great depth, they are forced to return to the surface to breath—dependent on internal oxygen reserves when underwater. The dive duration is approximately 27.5 to 30.2 minutes for females, while the males can dive for 42.0 to 51.4 minutes. What has been found is that most dives for the southern elephant seals show considerable variability in depth and duration, with behavioral variability reflecting the availability and distribution of prey—also reflecting the foraging success in the area.