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Northern Elephant Seal (Mirounga angustirostris)

Status | Species Description | Habitat | Distribution | Population Trends | Threats | Conservation Efforts | Regulatory Overview | Taxonomy | Key Documents | More Info

Status

MMPA - Northern elephant seals, like all marine mammals, are protected under the MMPA

Species Description

Weight:
males up to 4,400 pounds (2,000 kg);
females up to 1,300 pounds (600 kg);
pups are about 75 pounds (35 kg) at birth
Length:
males up to 13 feet (4 m);
females up to 10 feet (3 m);
pups are about 4 feet (1.2 m) at birth
Appearance:
pups are black until they are weaned at about 6 weeks old, they molt and turn light silver;
adults are dark brown or gray;
males develop a large inflatable nose, or "proboscis," when they reach puberty (around 7 years old)
Lifespan:
13-19 years, with females living longer than males
Diet:
mostly squid and fishes, but also rays and sharks
Behavior:
When they return to land to breed or molt, they fast.

Northern elephant seals are the largest phocid, or "true" seal, in the Northern Hemisphere. Fully grown males can reach lengths of over 13 feet (4 m) and can weigh nearly 4,400 pounds (2,000 kg). Females are significantly smaller than males, but are also quite large growing to about 10 feet (3 m) long and weighing up to 1,300 pounds (600 kg).

Pups are born in early winter from December to January. Breeding occurs from December to March, and gestation lasts around 11 months. Northern elephant seals are "polygamous"; males establish dominance over large groups of females during the breeding season.

Northern elephant seal pups are about 4 feet (1.2 m) long and weigh about 75 lbs (35 kg) at birth. Pups are generally black until they are weaned, when they are about 6 weeks old. They then molt and turn light silver. They gradually become darker brown or gray, though they often remain pale ventrally, or on their underside.

When males reach puberty at about 7 years old, they develop a large inflatable nose, or "proboscis." The proboscis overhangs their lower lip by about 8 inches (20 cm). They also develop a robust, thick neck that is heavily creased and lighter in color--even slightly pink--compared with their dark bodies. Conversely, females maintain their smaller noses and smooth necks.

There is also a notable difference in life span between males and females. Females generally live for about 19 years, while males only live for about 13 years.

When at sea, Northern elephant seals feed mostly on squid and fishes, but they also eat rays and even sharks. When they return to land to breed or molt, they fast. During these fasting periods, they can lose up to half of their body mass!

Habitat

Northern elephant seals spend much of the year, generally about 9 months, in the ocean. They are usually underwater, diving to depths of about 1,000-2,500 feet (330-800 m) for 20-30 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.

Distribution

Northern elephant seals are found in the eastern and central North Pacific Ocean. Though they range as far north as Alaska and as far south as Mexico, they typically breed in the Channel Islands of California or Baja California in Mexico.

Population Trends

Once thought to be extinct due to commercial sealing in the 1800s, the population began to steadily increase in the early 1900s. Though a complete population count of elephant seals is not possible because all age classes are not ashore at the same time, the most recent stock assessment reports with population estimates are available on our website.

Threats

Regulatory Overview

Northern elephant seals, like all marine mammals, are protected under the Marine Mammal Protection Act (MMPA) of 1972.

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Phocidae
Genus: Mirounga
Species: angustirostris

Key Documents

(All documents are in PDF format.)
Title Federal Register Date
Stock Assessment Reports - various

More Information

Updated: January 16, 2015