There are two species of elephant seal. Southern elephants seals are the larger of the two and live in Antarctica; northern elephant seals breed off the California coast. These large seals are named for the inflatable trunk-like nose found on males of the species. In addition to the elephantine facial appendage, male elephant seals also weigh eight to 10 times more than females -- the greatest size difference between males and females of any mammalian species.
The largest southern elephant seals weigh nearly 9 tons and are 20 feet long. Northern elephant seals are still massive, weighing up to 5 tons and reaching 16 feet in length. Aside from their distinctive facial features, elephant seals have hind limbs that are used as tail fins when swimming. The two fins on either side of their bodies are not used for swimming, but propel their bulky bodies forward on land.
Elephant seals are solitary in the ocean, but on land they form large colonies around their breeding grounds. These heavy animals are best adapted to the sea and clumsy on land, but can move at speeds up to 5 miles per hour if threatened. In practice, elephant seals only charge if vocalizations and posturing do not scare off their rival. Because males routinely fast for months while defending their breeding grounds, they prefer not to expend energy charging after challengers. While great white sharks and killer whales prey on elephant seals in open water, they have no predators on land apart from humans.
Elephant seals only come on land during breeding and molting seasons, spending 85 to 90 percent of their lives deep underwater. Southern elephant seals routinely travel thousands of miles away from their breeding grounds. These marine mammals feed exclusively at sea, hunting squid, crustaceans, fish, smaller sharks and other oceanic life. Their longest dives last two hours, with only a couple minutes between dives spent breathing at the surface.
Once heavily hunted for its blubber, the northern elephant seal was nearly extinct in the 1800s. The southern elephant seal was hunted as well, but never as extensively as the northern given the isolation of its Antarctic breeding grounds. With national and international laws in place to protect the northern elephant seal and prohibit commercial hunting, the species population has rebounded to an estimated 175,000 adults in 2013, according to the Wildlife Conservation Society.
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