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Kingdom
Animalia
Phylum
Chordata
Subphylum
Vertebrata
Class
Mammalia
Order
Carnivora
Suborder
Caniformia
Family
Phocidae
Species
Erignathus barbatus
Erignathus barbatus
bearded seal
2010/02/07 02:47:15.322 US/Eastern
By Heather Lutz
Species:
Erignathus barbatus
Geographic Range
Bearded seals are found in the waters around Alaska, the Arctic Ocean and in the "areas of the Bering, Chukchi, and Beaufort Seas where the ice forms during the winter" (Burns, 1994). They have also been known to go as far as China, Tokyo Bay, Scotland and northern Spain (Macdonald, 1985).
(
Burns, 1994
;
Macdonald, 1985
)
Habitat
Bearded seals prefer shallow, arctic waters less than 200 meters in depth. They also prefer broken, drifting patches of ice, although they readily adapt to dense, slow moving ice by making breathing holes. During the warmer months they sometimes climb ashore to gravel beaches.
(
Nowak, 1999
;
Parker, 1990
;
Seal Conservation Society, 1999
)
Terrestrial Biomes:
icecap.
Physical Description
Mass
216 to 360 kg
(475.2 to 792 lbs)
Length
2.50 m (average)
(8.2 ft)
Bearded seals have a gray or brown coat that is darker on their back than their underside. They are heaviest in the winter and early spring when they can weigh up to approximately 360 kg, although the largest they get is when a female is pregnant. In the spring, they decrease their food intake and loose some of their blubber and mass, weighing 216 kg to 239 kg. Adults are generally the same size, though females may be slightly longer (adults average about 2.4 m to 2.5 m). The large body mass makes their round head and flippers look even smaller in comparison. Their large, wide muzzle contrasts with their small close set eyes. Bearded seals have long white whiskers, hence their name. At the end of each flipper are equal length digits (sometimes the third digit is slightly larger) which gives them a square appearance. The claws on the digits are very strong, unlike those on the hind flippers. Unlike most other earless seals, which have two retractable teats, bearded seals have four.
Pups are similar in color to adults but have a lighter face and a back that has broad,light colored stripes. A dark line extending from the head to between the eyes is sometimes apparent. They are about half of the size of the adults when born (about 1.3m) and weigh much less (about 30 or 40kg). (Jefferson, 1993, SCS, Haley, 1978)
(
Burns, 1994
;
Haley, 1978
;
Jefferson, Leatherwood, and Webber, 1993
;
Nowak, 1999
)
Reproduction
Number of offspring
1 (average)
Gestation period
11 months (average)
Time to weaning
24 days (average)
Bearded seal males produce whistling sounds that are audible underwater. Some studies suggest bearded seals male practice a form of lek polygyny, where females are attracted to males who display in a common area.
Bearded seals are primarily solitary animals except during breeding seasons, or when females are raising their pups. The gestation period is 11 months including a dormancy period of 2.5 to 3 months after conception. This dormancy occurs until July when the embryo starts developing rapidly. Their reproductive cycle is annual and females usually breed a fortnight after their pups are weaned.
(
Burns, 1994
)
Lifespan/Longevity
Female life spans can be up to 31 years while males usually live about 25 years.
Behavior
Bearded seals give birth on pack ice in mid-March to late April. Shortly after birth, pups are able to swim and can dive 75 meters deep to escape polar bears. Pups put on weight quickly, especially during the 12 to 18 days of nursing. Pups molt into the adult coat around the time of weaning, which occurs when it reaches approximately 85kg. "After the breeding season, many seals migrate northward with the retreating ice, returning southward again as the ice advances in autumn and winter" (Jefferson, 1993).
These solitary creatures are seen resting on floating ice with their head facing downward into the water. This is so they can quickly escape into the sea if pursued by a predator. Bearded seals ram their head into thin ice in order to create breathing holes. They have been known to dive to a depth of 200 meters, however, they mainly feed in shallow waters.
(
Burns, 1994
;
Haley, 1978
;
Jefferson, Leatherwood, and Webber, 1993
;
Macdonald, 1985
;
Nowak, 1999
)
Communication and Perception
Males of this species sing an audible, underwater song during breeding season. Their song consists of "a long, oscillating warble that may last for more than one minute, followed by a short, low-frequency moan. This sound is known to be made only by mature males during the spring and may be a proclamation of territory or breeding condition" (Nowak, 1999).
(
Nowak, 1999
)
Food Habits
Bearded seals eat invertebrates and fish that occur in the shallow marine areas they inhabit. By using their sensitive whiskers, they are able to easily track their favorite food items such as crabs, shrimp, clams, and snails. (Grzimek's,1990, Nowak, 1999)
Animal Foods:
fish; mollusks; aquatic crustaceans.
Predation
The dominant predators of bearded seals are polar bears. These seals, when on shore, stay close to the edge of the water for a quick escape if disturbed. They are also hunted in the water by killer whales.
(
Seal Conservation Society, 1999
)
Economic Importance for Humans: Positive
Bearded seals are often hunted for their hides and are an important component of arctic peoples' diet. "Bearded seal meat is the most desirable of the seals, and the hides are necessary for boat covers, raw-hide line, boot soles, and numerous other uses" (Burns, 1994). Seals are most successfully hunted in the spring when boats are able to move through the broken ice and when seals are migrating north. Bearded seals were previously hunted for their intestines to make waterproof clothing and blubber to obtain lamp oil. (Burns, 1994, Nowak, 1999)
Conservation Status
IUCN Red List:
[link]
:
Lower Risk - Least Concern.
US Federal List:
[link]
:
No special status.
CITES:
[link]
:
No special status.
Bearded seal populations seem to be stable, estimated population size, excluding Canada and Norway, is 500,000. However, they are difficult to count and there are some concerns that the population may be declining as a result of habitat loss and other disturbances. Their habitats are in danger from global warming, pollution from oil and gas extraction, and boat traffic. Also, "there is a potential for conflict between bearded seals and commercial fisheries, particularly in the central Bering Sea for species such as Tanner crabs, pink shrimp and clams, all components of the bearded seal diet" (SCS).
(SCS, Grzimek's,1990, Nowak, 1999)
For More Information
Find
Erignathus barbatus
information at
Contributors
Heather Lutz (author), University of Michigan.
Phil Myers (editor), Museum of Zoology, University of Michigan.
References
Haley, D. 1978.
Marine Mammals of Eastern North Pacific and Artic Waters
. Seatle, Washington: Pacific Search Press.
Jefferson, T., S. Leatherwood, M. Webber. 1993.
Marine Mammals of the World
. Rome, Italy: Food and Agriculture Organization of United Nations.
Macdonald, D. 1985.
Encyclopedia of Mammals
. New York, NY: Facts on File Publications.
Nowak, R. 1999.
Walker's Mammals of the World Sixth Ed. vol 2
. Baltimore Maryland: The Johns Hopkins University Press.
Parker, S. 1990.
Grzimek's Encyclopedia Mammals Vol.4
. New York,NY: McGraw-Hill Publishing Co..
2010/02/07 02:47:16.504 US/Eastern
To cite this page:
Lutz, H. 2000. "Erignathus barbatus" (On-line), Animal Diversity Web. Accessed February 09, 2010 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Erignathus_barbatus.html.
Disclaimer:
The Animal Diversity Web is an educational resource
written largely by and for college students
. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.
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Sponsored in part by the Interagency Education Research Initiative,
the Homeland Foundation and the
University of Michigan
Museum of Zoology
.
This material is based upon work supported by the
National Science Foundation
under Grants DUE-0633095 and DRL-0628151.
The ADW Team gratefully acknowledges their support.
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