Bearded seal
Bearded seal[1] | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Clade: | Pinnipedia |
Family: | Phocidae |
Genus: | Erignathus Gill , 1866
|
Species: | E. barbatus
|
Binomial name | |
Erignathus barbatus Erxleben, 1777
| |
Distribution of bearded seal |
The bearded seal (Erignathus barbatus), also called the square flipper seal, is a medium-sized pinniped that is found in and near to the Arctic Ocean.[3] It gets its generic name from two Greek words (eri and gnathos) that refer to its heavy jaw. The other part of its Linnaean name means bearded and refers to its most characteristic feature, the conspicuous and very abundant whiskers. When dry, these whiskers curl very elegantly,[3] giving the bearded seal a "raffish" look.[citation needed]
Bearded seals are the largest northern phocid. They have been found to weigh as much as 300 kg (660 lb) with the females being the largest. However, male and female bearded seals are not very dimorphic.[3]
The only member of the genus Erignathus, the bearded seal is unique in that it is an intermediate. Bearded seals belong to the family
Fossils first described in 2002 indicate that, during the Pleistocene epoch, bearded seals ranged as far south as South Carolina.[4]
Description
Distinguishing features of this
Bearded seals reach about 2.1 to 2.7 m (6.9 to 8.9 ft) in nose-to-tail length and from 200 to 430 kg (441 to 948 lb) in weight.[5] The female seal is larger than the male, meaning that they are sexually dimorphic.
Bearded seals, along with
The body fat content of a bearded seal is about 25–40%.[10]
Distribution
Bearded seals are extant in Arctic and
Although the range typically only extends down into subarctic areas bearded seals have been seen in Japan and China as well as extremely far south of their range in Germany, Netherlands, United Kingdom, France, Spain and Portugal.[12]
Hunting and diet
Primarily
Reproduction and lifecycle
Bearded seals give birth in the spring. In the Canadian Arctic, seal pupping occurs in May.[9] In Svalbard, bearded seals reach sexual maturity at 5 or 6 years of age.[18] Further south, in Alaska, most pups are born in late April.[clarification needed] Pups are born on small drifting ice floes in shallow waters, usually weighing around 30–40 kg (66–88 lb). They enter the water only hours after they are born, and quickly become proficient divers. Mothers care for the pups for 18–24 days, during which time the pups grow at an average rate of 3.3 kg (7.3 lb) per day. During this time, pups consume an average of 8 L (1.8 imp gal; 2.1 US gal) of milk a day. By the time they are weaned, the pups have grown to about 100 kg (220 lb).
Just before the pups are weaned, a new mating cycle takes place. Females ovulate at the end of their lactation period, but remain close to their pups, ready to defend them if necessary. During the mating season, male seals will "sing", emitting a long-drawn-out warbling note that ends in a sort of moan or sigh. This sound may attract females, or may be used by the males to proclaim their territory or their readiness for breeding. Males occupy the same areas from one year to the next.[19]
Like many Arctic mammals, bearded seals employ a reproductive strategy known as
Natural predators of the bearded seal include polar bears, who rely on these seals as a major food source.
Bearded seals are believed to live up to 31 years.[23]
Vocalization
The vocalizations produced by the bearded seal are very unique, possibly because their trachea is different from that of other Northern Pacific phocids. A majority of the rings in the trachea are incomplete with only a membrane attaching the two ends.[24]
The sounds of the bearded seal usually consist of a long oscillating trill lasting for a minute or more followed by a short, deep moan. This "song" is often repeated frequently.[24] The number of call types within a population can vary geographically, with four types found in Svalbard and eleven in the Western Canadian Arctic. The most frequent sounds are trills, moans, and sweeps. A sweep can be compared to a short trill.[25]
Bearded seals produce distinct trills from late March to late June, with a decline in rhythmicity in late May and June. This timeline coincides with their breeding and pupping season, which is from April to May. The repetitive and transmittable nature of bearded seal trills leads researchers to believe that they are utilized for communication, likely during courtship and breeding.[26] Males use these sounds to establish mating territories and communicate their fitness,[25] but it is likely that females produce these sounds as well.[26]
Underwater, bearded seal trills can be heard from a distance of over 30 km (19 mi), with some types of sounds traveling farther than others. This makes it possible for one animal to communicate with another animal that is far away, although acoustic degradation does occur as the sound passes through the environment. A seal must produce a trill with a sound-pressure of at least 100 dB at 1 m in order for the sound to propagate 30 km, meaning that bearded seals can likely produce sounds at this level.[26]
Conservation status
On March 28, 2008, the U.S.
Subspecies
There are two recognized subspecies of this seal:[1]
While the validity of these subspecies has been questioned, and is not yet supported by any molecular data,[4] analysis of the animals' calls does indicate a differentiation between different populations.[30]
Evolutionary history
Bearded seal fossils have been found to be as old as the early to mid Pleistocene. These early fossils were found in northern regions like England, Alaska, and Sweden, as well as the North Sea and the Champlain Sea.[31]
Bearded seals, like all true seals, belong to the family Phocidae which is one of the three families in the clade Pinnipedia, along with
Bearded seals belong to the subfamily Phocinae (Northern Hemisphere seals). Phocinae can be further divided into three clades: Erignathini (bearded seals), Cystophorini (hooded seals), and Phocini (all remaining genera). Bearded seals are the sister taxa to the common ancestor of Cystophorini and Phocini.[32]
See also
References
- ^ OCLC 62265494.
- ^ . Retrieved 12 November 2021.
- ^ ISBN 9780080919935.
- ^ .
- ^ Erignathus barbatus. The Animal Diversity Web
- PBS Nature. 17 February 2008. Archived from the originalon 9 February 2008. Retrieved 24 August 2017.
- ^ Ohokak, G.; M. Kadlun; B. Harnum. Inuinnaqtun-English Dictionary (PDF). Kitikmeot Heritage Society. Archived from the original (PDF) on 2012-09-04. Retrieved 2013-03-20.
- ^ "Bearded seal". Asuilaak Living Dictionary. Retrieved 2013-03-20.[permanent dead link]
- ^ a b "Ugjuk — Bearded Seal". Archived from the original on 2021-04-27. Retrieved 2013-03-20.
- ISSN 0706-652X.
- ISSN 0706-652X.
- ^ doi:10.2305/iucn.uk.2016-1.rlts.t8010a45225428.en.)
{{cite journal}}
: Cite journal requires|journal=
(help - S2CID 25532134.
- ^ ISSN 1923-1245.
- ^ "Bearded Seal - NAMMCO". NAMMCO. 2017-01-16. Retrieved 2018-06-07.
- ^ Saundry, Peter. 2010. Bearded seal Archived July 4, 2010, at the Wayback Machine. Encyclopedia of Earth. Topic editor C. Michael Hogan, Ed.in Chief: Cutler Cleveland, NCSE, Washington DC
- ISSN 1923-1245.
- S2CID 37623370.
- ^ Nuttal; et al. (2005). Encyclopedia of the Arctic. New York, NY: Routlelege.
- ^ Perry, Judith E. (1983). Seals of the World. Ithaca, NY: Comstock Publishing Associates. p. 103.
- ^ "Erignathus barbatus – bearded seal". Animal Diversity Web.
- ^ Folkens, Peter (2002). National Audubon Society Guide to Marine Mammals of the World. New York, pg. 117.
- ^ National Marine Mammal Laboratory Bearded Seals Retrieved May 1, 2016
- ^ a b Burns, John J. (May 1979). "Natural History and Ecology of the Bearded Seal, Erignathus Barbatus" (PDF).[permanent dead link]
- ^ S2CID 53187110.
- ^ ISSN 0008-4301.
- ^ Federal Register /Vol. 73, No. 61 / March 28, 2008 / Proposed Rules. National Marine Fisheries Service
- ^ Fisheries, NOAA (2018-05-24). "Bearded Seal | NOAA Fisheries". www.fisheries.noaa.gov. Retrieved 2018-06-06.
- doi:10.1139/z80-302.
- S2CID 53187110.
- ^ PMID 18494361.
- S2CID 135439365.
Further reading
- U.S. National Marine Fisheries Service bearded seal webpage
- Heptner, V. G.; Nasimovich, A. A; Bannikov, Andrei Grigorevich; Hoffmann, Robert S, Mammals of the Soviet Union, Volume II, part 3 (1996). Washington, D.C. : Smithsonian Institution Libraries and National Science Foundation
External links
- Recording of the bearded seal's unique "spiralling trill"
- The sound of the bearded seal
- Voices in the Sea – Sounds of the Bearded Seal Archived 2014-07-09 at the Wayback Machine
- Photos of Bearded seal on Sealife Collection