Male southern elephant seals, mirounga leonine, are the largest seals in the world. They can measure up to 20 feet (6 meters) in length while females only reach up to 10 feet (3 meters) long. Males weigh up to 8,157 pounds (3,700 kilograms) while females are only 881 to 1,984 pounds (400 to 900 kilograms). Males (bulls) have a long, trunk-like proboscis (hence the name) while females do not. These vast differences in appearance between genders make southern elephant seals the most sexually dimorphic (males and females of the same species differ in appearance) of all mammals. Both genders however, are silvery-brown skin, flipper tails and strong front flippers.
Southern elephant seals can be found around South America and Antarctica mostly. They prefer to inhabit beaches, rocky terrain and even ice and snow during the breeding season. Throughout the rest of year, southern elephant seals will spend their time in the ocean feeding and will only haul out of the water once or twice. They are so big however, that it makes it difficult to get themselves out of the water, explaining why they only do it a limited number of times a year. Southern elephant seals can dive up to 3,200 feet (975 meters) into the water and remain under for up to 2 hours. They can remain under water for so long by reducing their heart rate to 1 beat per minute.
The diet of southern elephant seals consists mainly of squid and large fish, although they also feed on crustaceans and ascidians. If food is scarce, then they may even eat penguins that are close to their habitat. Their incredible diving and swimming skills allow them to catch their prey with minimal effort. Since southern elephant seals are such large creatures they have practically no natural predators to watch out for.
During the breeding season, southern elephant seals will haul themselves out of the water and on to land to give birth and mate. Males will arrive before the females do and establish a territory. After the females arrive they will form a large group, called a harem that will be dominated by a single male (although large harems may have 1 or 2 more subdominant males that will also breed with the females). The males will fight off any other males that might try to mate with the harem. The pregnant females will give birth to a single pup 2 to 5 days after arriving on the breeding grounds. The pups will nurse for about 23 days, but the mothers will have mated with the dominant male several days before weaning takes place. After the pups have been weaned, the females will return to the ocean and leave the pups to fend for themselves. Pups will remain either on shore or in the shallows for about 4 to 6 weeks before they venture out into the ocean by themselves.
Southern elephant seals are a protected species. Their current population is better than it has been in the past, but is still a ways off from being at a comfortable level. Hopefully, continued protection of southern elephant seals and their breeding grounds will keep them from having to face the threat of extinction. After all, such a unique and massive creature deserves to live and prosper far into the future.
Works Cited
“Species: Southern Elephant” 23 February 2011
“Southern Elephant Seal (Mirounga Leonina)” February 2011
