Northern Elephant Seal (Mirounga angustirostris)

 

Class: Mammalia
Order: Carnivora Suborder: Pinnipedia
Family:    Phocidae
Size:    Length: 10 to 14 feet (3 to 4.26 m)
Weight: 2,000 to 5,000 pounds (907 to 2268 kg)
Diet: Many different kinds of fish, including squid, octopus, eel and even small sharks
Distribution: Pacific Ocean along the North American coast
Young:  1 pup, once per year
Animal Predators:  Killer whales and great white sharks
IUCN Status: No special status
Terms: Male: Bull  Female: Cow  Young: Pup
Lifespan: Average 14 years

 

Facts/Trivia:

·         The northern elephant seal is the second largest seal in the world—only the southern elephant seal is larger.

·         Approximately two-thirds of males never get the chance to breed.

·         The northern elephant seal’s milk is richer in fat (54.5 percent) than any other mammal.

·         Female elephant seals who have lost their own pups sometimes adopt orphaned pups.

·         Bull elephant seals fast during breeding season, and may lose up to one-half of their body weight.

 

Description

It is easy to distinguish elephant seal males from females—males have an elongated nose that resembles an elephant’s trunk. Elephant seals are large seals, and move awkwardly on land. Males are much larger and darker than females. They use their hind flippers to swim. Their front flippers are relatively small and have flexible digits that they use for scratching and for scooping sand over their body. 

 

Habitat

Northern elephant seals live in the coastal waters of the Pacific Ocean from British Columbia to Mexico, but they mostly breed along the coast of California. They haul up on deserted islands or remote beaches along the mainland. 

 

Feeding Habits

Elephant seals have sharp canine teeth and eat many different kinds of fish, including squid, octopus, eels and even small sharks. Northern elephant seals do not eat during the breeding season, losing as much as 10 to 15 pounds (4.5 to 7 kg) per day. 

 

Reproduction

Mating season begins in December, when the males arrive at the breeding grounds. They fight to establish territories, and then wait for the females to arrive. One male may enjoy a harem of up to 40 females, while others—up to one third of the males—do not get the chance to mate at all. The females give birth a few days after arriving on the beach, following an 11-month pregnancy. The dark brown or black-furred baby weighs 65 to 75 pounds (29 to 34 kg) at birth and is nursed for approximately one month. The pup gains 10 pounds (4.5 kg) per day, drinking its mother’s rich, fat milk. Just before the pup is weaned, the female mates with a dominant male. When the baby is fully weaned, she returns to sea, leaving it behind. The pup moults at about that time, shedding its black coat for a silver gray coat. Weighing approximately 400 pounds (181 kg) by the time they are weaned, pups stay on the beach where they were born, living in groups with other pups. They spend their time entering the water to perfect their swimming and hunting abilities. Their mothers return in spring, when it is time for them to moult. Afterwards, the females and their youngsters head out to sea. Male elephant seals begin to develop their enlarged nose when they reach maturity, sometime from three to five years of age. The nose is fully developed by nine years. 

 

Behaviour

Both males and females spend most of their time at sea, but come ashore during breeding season, and also when it is time to moult their skin. Females and their offspring are the first to moult, in late spring, while young males moult from May to June and adult males moult during July and August. They arrive on deserted beaches and lie down, one next to another, as their skin and fur moult away. They usually lie in muddy water to keep cool. Once they have completed their moult, during which they shed their entire outer layer of skin, leaving the pieces on the beach, the seals return to the water until breeding season, which begins in December. They can remain underwater for up to 80 minutes and dive as deep as 4,000 feet (1,219 m), deeper than any other seal.

 

Conservation

In the 1800s, elephant seals were killed in large numbers for their blubber, which was made into lamp oil. Entire herds were quickly slaughtered when they arrived on land for moulting or breeding seasons, because of their slow movement on land. In the 1860s, kerosene was invented and had become a popular alternative fuel, but it appeared to be too late, as by the late 1800s, elephant seals were believed to be extinct. In 1892, a hunting party looking for fur seals came across a handful of elephant seals on Guadalupe Island. The hunters killed almost all of them to study them, further endangering their survival, but miraculously, in 1911, approximately 100 were found on that same island, and the Mexican government immediately passed a law partially protecting them. In 1922, they went a step further and passed a law to fully protect the elephant seals from hunting or harassment.

 

Sources

http://animaldiversity.ummz.umich.edu/accounts/mirounga/m._angustirostris$narrative.html

http://www.oceanoasis.org/fieldguide/miro-ang.html

http://www.rcjokelist.com/e-seal.html

http://www.pinnipeds.fsnet.co.uk/species/nelephnt.htm

http://pinnipedlab.ucsc.edu/pinniped/miro.html

http://www.washington.edu/burkemuseum/mammalogy/mian.html

http://ourworld.compuserve.com/homepages/jaap/elepseal.htm

http://www.nature.ca/notebooks/english/eleseal.htm

Elephant Seal Wildlife Fact File, IM Pub, US