Introduction & History
The northern elephant seal is the largest of the “true” seal in the Northern Hemisphere. Adult males use their large, inflatable noses during the winter breeding season to resonate sound when vocally threatening each other. The largest colonies of northern elephant seals are found off southern California in the Channel Islands. They have one of the longest migrations of any mammal; some have been recorded traveling over 13,000 miles roundtrip.
Northern elephant seals were once thought to be extinct due to commercial sealing in the 1800s. Populations of northern elephant seals in the U.S. and Mexico were all originally derived from a few hundred individuals surviving in Mexico. Its population began to steadily increase in the early 1900s.
Northern elephant seal pups are black until they are weaned at about 6 weeks old, when they molt and turn light silver. Adults are dark brown or gray.
When males reach puberty at about 7 years old, they develop a large inflatable nose (proboscis). The proboscis overhangs their lower lip by about 8 inches. They also develop a robust, thick neck that is heavily creased and lighter in color than their dark bodies. Conversely, females maintain their smaller noses and smooth necks.
Fully grown males can reach lengths of over 13 feet and can weigh nearly 4,400 pounds. Females are significantly smaller than males, but are still grow to about 10 feet long and weigh up to 1,300 pounds.
Northern elephant seals are found in the coastal waters of the Pacific Ocean from the Gulf of Alaska down to Baja California. Foraging migrations by males and females are made separately, two times yearly. Males journey north to the Aleutian Islands and the Gulf of Alaska. Females don't travel as far north, but instead migrate further west to more open ocean. The total linear distances migrated by these animals each year has been recorded at 21,000 km. Seals can be seen on shore most often from December through March, during the mating season and again beginning in April and continuing through August as they haul out for moulting.
Behavior & Diet
Northern elephant seals have a diet of mostly squid and fishes, but also rays and sharks.
Northern elephant seals spend much of the year—generally about 9 months—in the ocean. They are usually underwater, diving to depths of about 1,000 to 2,500 feet for 20 to 30 minute intervals with only short breaks at the surface. They are rarely seen out at sea for this reason. While on land, they prefer sandy beaches.
They fast during mating season and can lose up to 36 percent of their body weight during this time. When molting occurs, they shed their short, dense fur along with large patches of old skin. Molting takes from 4 to 5 weeks to complete.
Hundreds of thousands of northern elephant seals lived in the Pacific Ocean before hunters slaughtered them for their blubber, which was used to make lamp oil. By the late 1800s, the only remaining colony — fewer than 100 seals — lived on Mexico’s Guadalupe Island. To save them, the Mexican government gave protected status to northern elephant seals in 1922. A few years later, when elephant seals began appearing in southern California waters, the United States gave the seals the same protection. As a result, the population of northern elephant seals is about 160,000 today. The elephant seal’s mighty comeback is an example of the importance of protective status and marine sanctuaries in ocean conservation.
The elephant seal, like other mammals, must replace old skin and hair. Most mammals shed hair year-round, but the elephant seal does it all at once. Once each year, the seal comes ashore and sheds the first layer of skin and fur, which come off in sheets as new skin and fur replace the old.
Sourced From/More Information:
Article 1 & Images: https://www.fisheries.noaa.gov/species/northern-elephant-seal