Sea Elephant . Marine mammal that owes its name to the trunk that the males present.
Summary
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- 1 Scientific classification
- 2 Features
- 3 Food
- 4 Mating and breeding
- 5 State of Conservation
- 6 sources
scientific classification
The sea elephant belongs to the family of the Phocids, which is included in the order of the Pinnipeds; for some authors the Pinnipeds are a suborder within the order of the Carnivores.
The northern elephant seal is classified as Mirounga angustirostris and the southern elephant seal as Mirounga leonina.
Characteristic
Within mammals, the elephant seal is the species with the greatest difference in size between the two sexes. Adult males can reach 4.8 m in length and 3,000 kg in weight. The females measure about 3 m and weigh 900 kg at most. Male northern elephant seals have a slightly longer trunk and dark brown skin, while southern elephant seals have blue-gray skin.
The male is not only distinguished by its size and trunk, but also by the scars that adorn its neck and chest. Those scars are a legacy of battles with other males for female dominance. The difference in size of the females, as well as the aggressiveness of the male, puts her at risk of suffering damage during mating.
Like many other mammals, the elephant seal sheds its skin every year. The molting process takes place on land, in the breeding grounds. Northern elephant seal breeding grounds are located on remote islands off the coast of California and Mexico . The breeding grounds for southern elephant seals are found on the Valdés Peninsula , off the coast of South America . After molting, elephant seals spend several months foraging in the ocean, after which, well fed, they gather back on shore to mate.
The elephant seal is considered the best diver of all mammals. Attaching a radio device to these animals and following them by satellite, scientists have recorded dives of up to 1.6 km and lasting more than 2 hours. The researchers are especially interested in studying the deep dives of the elephant seal and the readjustment it makes to breathe when it comes to the surface.
That readjustment includes swelling of collapsed lungs and other processes that restore blood flow. This recovery phase usually causes serious damage to the organs of human beings. By studying the physiology of these animals, scientists hope to find clues that allow humans to survive strokes, heart attacks and serious injuries.
It is the largest existing pinniped and also the heaviest. There are two species of elephant seal: the northern or northern elephant seal, which lives near the southwestern coast of the United States and Mexico and sometimes ranges as far north as Alaska ; and the southern or southern elephant seal, which inhabits the southern and subantarctic oceans , with notable populations clustered around the Falkland Islands , the Kerguelen Islands , in the southern Indian Ocean, and on Macquarie Island , located southeast of Tasmania , Australia .
Feeding
When foraging at sea , elephant seals spend nearly 24 hours a day diving into deep water to catch their favorite food: bottom-dwelling fish such as chimaera and dogfish . They also eat squid , eels , small sharks , and algae .
mating and breeding
The breeding season is in December and January for northern elephant seals and in September and October for southern elephant seals. During the mating season, a combination of blood pressure and muscular action swells the male elephant seal’s distinctive bulge, which reaches a length of 30 to 45 cm. Wearing this impressive sexual distinctiveness, the males arrive at the breeding ground or colony, to mark their territory, challenge and roar at other males, and sometimes fight them.
Females arrive at the colony a few weeks later, each giving birth to a single, black, furry pup shortly after reaching shore. Mothers and calves soon learn to distinguish their calls, sometimes joining in vocal duets. That knowledge is essential for the survival of the hatchlings, since bad weather, strong waves or the fights of the males can separate the mothers from the young. Using vocalizations, they can meet again.
The young feed on the rich milk of their mothers for almost a month. During that time the mothers fast, losing up to 135 kg. Elephant seal pups, which weigh 34 kg at birth, gain at least 4.5 kg a day. Some daring young feed on two or three females. These gluttonous pups can reach 270 kg, almost double the weight of a normal pup. Females mate at weaning time; later, they return to the sea, where they spend the gestation period, which lasts almost a year, before returning to the colony.
State of conservation
Elephant seals are natural prey for killer whales and sharks. During the 19th century , the elephant seal was hunted almost to extinction by humans for its fat, which was turned into oil . They were especially appreciated prey, because their huge bodies provided a lot of fat – up to 658 kg per animal. By 1892 only 50 to 100 northern elephant seals remained, grouped near Guadalupe Island off Baja California .
Southern elephant seal populations have also declined alarmingly. Since then, both species are protected by the various governments that have jurisdiction over the waters in which the two species live. For example, the northern elephant seal is fully protected by the United States and Mexico. As a result of this protection, the population of both species has undergone a spectacular recovery.
