Crabeater Seal

Scientific Classification

Common Name

crabeater seal

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Pinnipedia

Family

Phocidae

Genus Species

Lobodon carcinophagus

Fast Facts

Description

The crabeater seal is a slender, streamlined seal with silvery gray to whitish fur and a long, slightly upturned snout. Younger crabeater seals have small specks and webs of brown or dark gray over much of their dorsal side. Pups are grayish brown with very light scattered spots.

Size

Both males and females may reach 2.6 m (8.53 ft.) in length

Weight

Weigh up to 225 kg (496 lbs.): large individuals up to 300 kg (660 lbs.).

Diet

Feeds primarily on Antarctic Krill, Euphausia superba, which accounts for over 90% of their diet, with the remainder made up of fish and squid.

Gestation

Approximately 11 months for total gestation, with a 2.7 month period of delayed implantation: newborns are 1.1 m (3.6 ft.) and 20 to 40 kg (44 to 88 lbs.)

Estral Period

Typically 4 days after weaning

Nursing Duration

Approximately 14 to 28 days (average 17 days)

Sexual Maturity

2 to 6 years: the mean age of sexual maturity in females varies from 2.5 to 4.2 years and these variations may be related to changes in food abundance.

Life Span

May be up to 39 years

Range

The distribution of the crabeater seal is tied to seasonal fluctuations of the pack ice. They can be found right up to the coast and ice shelves of Antarctica, as far south as the Bay of Whales (Lindsey 1938), during late summer ice break-up. They occur in greatest numbers in the seasonally shifting pack ice surrounding the Antarctic continent. As vagrants they travel as far north as New Zealand and the southern coasts of Africa, Australia and South America.

Habitat

Inhabits pack ice

Population

Global: The most recent available data, obtained during the multi-national effort conducted under the umbrella of the Antarctic Pack Ice Seal program in the late 1990s, provided a population size estimate of approximately 8,000,000 animals for the area surveyed. Considering that major areas of the pack ice around the continent were not surveyed, there is a large uncertainty regarding the actual population size of the species. Yet, crabeater seals are considered to be one of the most abundant seal species (if not the most abundant) and one of the most numerous large mammals on Earth.

Status 

IUCN: Least concern
CITES: Not listed
USFWS: Not listed

Fun Facts

1. Crabeater seals belong to the scientific order Pinnipedia, which includes seals, sea lions, and walruses.
2. Seals differ from sea lions in a number of ways, including having no visible earflaps.
3. Antarctic seals tend to have longer, more pointed foreflippers than northern phocids.
4. Their unique teeth allow crabeater seals to strain krill out of seawater.
5. Crabeater seals are unique among phocids in that this species forms family groups consisting of an adult female, her pup, and an adult male. The male usually joins a pregnant female shortly before or after the pup's birth and remains with the female until after the pup is weaned and mating occurs. During the time a family group is together, the adult male defends the female and pup from other adult males.
   
    

Ecology and Conservation

Many crabeater seals often bear scars from leopard seal and, to a lesser extent, from killer whale attacks. Mortality is high in the first year, possibly reaching 80%. Much of this mortality is attributed to Leopard Seal predation, and up to 78% of Crabeaters that survive through their first year have injuries and scars from Leopard Seal attacks.

Scientists consider crabeater seals to be the most abundant of any pinniped species.

The crabeater seal is protected by the Antarctic Treaty and the Convention for the Conservation of Antarctic Seals and any future commercial harvest would have to be regulated through these international agreements.

Bibliography

Bonner, N. Seals and Sea Lions of the World. New York. Facts on File, Inc. 2004.

Byrum, J. Pinnipeds From Pole to Pole: Seals, Sea Lions and Walruses. SeaWorld Education Department Publication. San Diego. SeaWorld, Inc. 2000.

Jefferson, T.J. Leatherwood, S. and M.A. Webber. FAO Species Identification Guide. Marine Mammals of the World. Rome. FAO, 1993.

Larws, R.M., Baird, A. and M.M Bryden. "Breeding season and embryonic diapause in crabeater seals (Lobodon carcinophagus)". Reproduction. 126: 365-370. 2003.

Nowak, Ronald M. (ed.). Walker's Marine Mammals of the World. Baltimore: Johns Hopkins University Press, 2003.

Parker, S. (ed.). Grizmek's Encyclopedia of Mammals. Vol. IV. New York: McGraw-Hill Publishing Co., 1990.

Reeves, R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell (Peter Folkens illustrator). National Audubon Society: Guide to Marine Mammals of the World. New York: Random House, 2002.

Reeves, R.R., Stewart, B.S. and S. Stephen. The Sierra Club Handbook of Seals and Sirenians. San Francisco: Sierra Club Books, 1992.

Ridgway, S.H. and R.J. Harrison (Eds). Handbook of Marine Mammals: Volume 2: Seals. London. Academic Press, 1981.

Riedman, M. The Pinnipeds: Seals, Sea Lions and Walruses. Berkeley and Los Angeles. University of California Press. 1990.