Hubbry Logo
Bearded sealBearded sealMain
Open search
Bearded seal
Community hub
Bearded seal
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Bearded seal
Bearded seal
Bearded seal
View on Wikipedia
from Wikipedia

Bearded seal[1]
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Phocidae
Subfamily: Phocinae
Tribe: Erignathini
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 Phocidae which contains two subfamilies: Phocinae and Monachinae. The bearded seal possesses characteristics of both of these subfamilies.[3]

Fossils first described in 2002 indicate that, during the Pleistocene epoch, bearded seals ranged as far south as South Carolina.[4]

Description

[edit]

Distinguishing features of this earless seal include square fore flippers and thick bristles on its muzzle. Adults are greyish-brown in colour, darker on the back; rarely with a few faint spots on the back or dark spots on the sides. Occasionally the face and neck are reddish brown. Bearded seal pups are born with a greyish-brown natal fur with scattered patches of white on the back and head. The bearded seal is unique in the subfamily Phocinae in having two pairs of teats, a feature it shares with monk seals.

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 ringed seals, are a major food source for polar bears.[6] They are also an important food source for the Inuit of the Arctic coast. The Inuit language name for the seal is ugjuk[7][8] (plural: ugjuit) or oogrook or oogruk. The Inuit preferred the ringed seal for food and light; the meat would be eaten and the blubber burnt in the kudlik (stone lamp). The skin of the bearded seal is tougher than regular seal and was used to make shoes, whips, dog sled harnesses, to cover a wooden frame boat, the Umiak and in constructing summer tents known as tupiq.[9]

The body fat content of a bearded seal is about 25–40%.[10]

Distribution

[edit]

Bearded seals are extant in Arctic and subarctic regions. In the Pacific region, they extend from the Chukchi Sea in the Arctic, south into the Bering Sea[11] where they span from Bristol Bay on the Alaskan coast to the Sea of Okhotsk on the Russian coast,[2] up to but not including the northern coast of Japan.[2] In the Arctic Ocean, they are found along the northern coasts of Russia, Norway, Canada, and Alaska,[2] including the Norwegian Archipelago of Svalbard[12] and Canadian Arctic Archipelago.[13] In the Atlantic, Bearded seals are found along the northern coast of Iceland, the east and west coasts of Greenland and the Canadian mainland as far south as Labrador.[14]

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.[2]

Hunting and diet

[edit]

Primarily benthic, bearded seals feed on a variety of small prey found along the ocean floor, including clams, squid, crustaceans, and fish.[5] Their whiskers serve as feelers[15] in the soft bottom sediments. Adults tend not to dive very deep, favoring shallow coastal areas no more than 300 m (980 ft) deep. Pups up to one year old, however, will venture much deeper, diving as deep as 450 m (1,480 ft). In a study conducted during the summer months, the seals have been found to feed on invertebrates such as anemones, sea cucumbers, and polychaete worms.[13] The same study found that flatfishes (such as American plaice), sculpins, and Arctic cod made up most of their summer diet.[5] Sculpin were also found to be the largest fish consumed by the seals. Bearded seals are capable of preying on pelagic and demersal fish in addition to their benthic prey.[16]

Reproduction and lifecycle

[edit]
Bearded seal pup

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.[17] 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.[18]

Like many Arctic mammals, bearded seals employ a reproductive strategy known as delayed implantation. This means that the blastocyst is not implanted for two months after fertilization, most often becoming implanted in July. Thus, the seal's total gestation period is around eleven months, though its active gestation period is nine months.[19]

Natural predators of the bearded seal include polar bears, who rely on these seals as a major food source.[5] Killer whales also prey on these seals, sometimes overturning ice floes to reach them. Walruses also eat these seals, mainly pups, but such predation is rare.[20]

Bearded seals are believed to live up to 31 years.[21]

Vocalization

[edit]

The vocalizations produced by the bearded seal are 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.[22]

Sample of underwater bearded seal vocalizations taken using a hydrophone

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.[22] 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.[23]

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.[24] Males use these sounds to establish mating territories and communicate their fitness,[23] but it is likely that females produce these sounds as well.[24]

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.[24]

Bearded seal on ice, Svalbard

Conservation status

[edit]

On March 28, 2008, the U.S. National Marine Fisheries Service initiated a status review[25] under the Endangered Species Act (ESA) to determine if listing this species under the ESA is warranted. All bearded seals are protected under the Marine Mammal Protection Act, and determined by the IUCN to be classified as a "least concern" for extinction.[2] This classification was determined due to various factors including, widespread distribution, stable population size, as well as alternating prey resources. NOAA determined that the factors influencing any change in conservancy status of the bearded seal may include: loss of sea ice by climate change, bycatch from commercial fishing gear, and hunting.[26] Their main predators include polar bears; however, typically pups around age 2 are attacked within birthing lairs, leaving older juveniles and adults commonly unharmed.[27] Due to climate change, factors such as loss of sea ice, as well as decrease in prey population may create negative results on the bearded seal population in the future. Therefore, monitoring of the species as well as influences of human activity, will be vital to ensure species stability.

Subspecies

[edit]

There are two recognized subspecies of this seal:[1]

Image Subspecies Distribution
Erignathus barbatus barbatus (Erxleben 1777) – Eastern bearded seal
Erignathus barbatus nauticus (Pallas 1811) – Western bearded seal

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.[23]

Bearded seal face.

Evolutionary history

[edit]

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.[28]

Bearded seals, like all true seals, belong to the family Phocidae which is one of the three families in the clade Pinnipedia, along with Otariidae and Odobenidae. Pinnipeds are thought to have originated 27 to 25 million years ago during the late Oligocene period. One hypothesis for the evolution of pinnipeds is that pinnipeds are a diphyletic group and otariids and odobenids are more closely related to bears, and phocids are more closely related to mustelids like weasels. Another hypothesis suggests that pinnipeds are a monophyletic group that descended from a single ancestor. This has been more supported by phylogenetic analysis than the diphylectic hypothesis. One such study suggests that phocids are sister taxa to the common ancestor to both otariids and odobenids.[28]

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.[29]

See also

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Bearded seal

View on Grokipedia
from Grokipedia
The bearded seal (Erignathus barbatus) is a large true seal of the family Phocidae, native to Arctic and sub-Arctic waters of the Northern Hemisphere, where it is distinguished by prominent, bristly vibrissae that resemble a beard and give the species its common name. As the largest seal in the Arctic, adults typically measure 2.1 to 2.7 meters in length and weigh 200 to 430 kilograms, with females generally larger than males. These solitary animals prefer shallow coastal waters under 200 meters deep, closely tied to seasonal pack ice for hauling out, breeding, and molting, and they exhibit a circumpolar distribution generally south of 80° to 85° N latitude. Bearded seals primarily forage on the seafloor for benthic invertebrates and fish, employing their sensitive whiskers to detect prey in low-visibility conditions. During the spring breeding season from late March to mid-May, males produce characteristic underwater vocalizations—such as trills, moans, and sweeps—to attract females, often from isolated ice floes, with reproduction being promiscuous and lacking paternal care. The species faces significant threats from climate-driven sea ice decline, which disrupts breeding and foraging habitats, leading to its recent reassessment as Near Threatened on the IUCN Red List in 2025. In the Pacific, the Beringia and Okhotsk distinct population segments are classified as threatened under the U.S. Endangered Species Act, reflecting concerns over population stability estimated in the hundreds of thousands globally.

Taxonomy and Phylogeny

Classification and Nomenclature

The bearded seal (Erignathus barbatus) is a within the monotypic genus Erignathus, classified in the Phocidae (true seals or earless seals), subfamily (northern seals), order , class Mammalia, phylum Chordata, and kingdom Animalia. This placement reflects its phylogenetic position among caniform carnivorans adapted to marine environments, with molecular evidence supporting the division of Phocidae into Phocinae and the southern subfamilies. The species was first scientifically described by Johann Christian Polycarp Erxleben in 1777 under the basionym Phoca barbata, later reclassified into the genus Erignathus to distinguish its morphological traits from other phocids. The genus name Erignathus derives from Greek roots "eri-" (an intensive prefix denoting "very" or "much") and "gnathos" (jaw), referencing the seal's prominent, robust jaw structure. The specific epithet barbatus is Latin for "bearded," alluding to the dense, vibrissae-covered muzzle that resembles a beard and aids in benthic foraging. These names emphasize observable anatomical features rather than behavioral or ecological traits, consistent with Linnaean conventions prioritizing morphology in pinniped taxonomy.

Subspecies

The bearded seal (Erignathus barbatus) is classified into two subspecies based on geographic isolation and minor morphological distinctions, though genetic differentiation between them is limited. These are E. b. barbatus (Atlantic bearded seal) and E. b. nauticus (Pacific bearded seal), with the former inhabiting Arctic regions of the North Atlantic and the latter occurring in the North Pacific. Subspecies designations persist despite overlapping traits, primarily due to allopatric distributions that limit gene flow, as evidenced by studies showing low but detectable divergence.
SubspeciesDistributionKey Notes
E. b. barbatus, , North including Larger-bodied on average; historically described by Erxleben in 1777.
E. b. nauticus, , , and adjacent Pacific Arctic watersSubject to U.S. stock assessments; described by Pallas in 1811; faces threats from sea ice loss in .
The E. b. barbatus subspecies ranges across eastern Arctic waters, from the western eastward through the and into the North Atlantic as far south as Newfoundland, with vagrants recorded in European coastal areas. Populations here exhibit seasonal migrations tied to ice formation, with breeding concentrations in areas like where ice cover supports whelping. In contrast, E. b. nauticus predominates in the Pacific sector, encompassing the Bering, Chukchi, and seas, where individuals haul out on seasonal pack ice and show fidelity to specific foraging grounds like the Gulf of Anadyr. Abundance estimates for the Pacific subspecies indicate approximately 150,000–200,000 individuals in U.S.-managed stocks as of 2019 assessments, though precise counts remain challenging due to wide-ranging behavior. Morphological differences between subspecies are subtle, including slight variations in skull proportions and pelage coloration, with Pacific individuals often displaying darker, more mottled coats adapted to variable ice conditions. Genetic analyses, such as sequencing, reveal shallow divergence (e.g., 0.5–1% sequence variation), supporting recognition as rather than full , as interbreeding could occur if ranges overlapped historically. Conservation efforts, including Endangered Species Act listings for E. b. nauticus in 2012, reflect subspecies-specific vulnerabilities to climate-driven ice decline, which disproportionately affects Pacific populations reliant on habitats. No additional are currently recognized by major taxonomic authorities, despite occasional proposals for further subdivision based on regional .

Evolutionary History

The family Phocidae, to which the bearded seal (Erignathus barbatus) belongs, originated during the late to early , approximately 27–20 million years ago, in the North Atlantic and Mediterranean regions, as evidenced by early fossils such as Noriphoca species. This divergence reflects adaptations from terrestrial arctoid carnivoran ancestors to fully aquatic lifestyles, with phocids developing hindlimb propulsion distinct from the forelimb-dominant swimming of otariids and odobenids. Within Phocidae, the subfamily —encompassing northern true seals including Erignathus—emerged after the basal split from the southern , likely in the , with phylogenetic evidence indicating environmental pressures drove specialized traits like enhanced insulation and ice-associated behaviors. Molecular analyses of coding regions position Erignathus as a distinct, early-diverging lineage within , basal to clades containing genera such as Phoca, , and Cystophora, supporting a northern hemispheric radiation tied to cooling climates and polar ice formation. Phocid diversification involved multiple equatorial crossings, enabling global spread while northern lineages like conformed to, yet occasionally deviated from, Bergmann's ecogeographical rule through body size adjustments in response to and prey availability gradients. The fossil record specific to Erignathus barbatus begins in the Early to Middle Pleistocene, with remains documented from marine deposits in , , and Cape Deceit, , indicating an established Arctic-subarctic presence by this period. Additional Pleistocene fossils from North Atlantic coastal sites, including , reveal a distribution overlapping modern ranges, with specimens dated between approximately 13,000 and 12,100 years ago in shallow environments. These records align with glacial-interglacial cycles, where retreating ice sheets facilitated southward extensions. Genetic surveys of contemporary populations demonstrate low to moderate diversity, with subspecies E. b. barbatus (Atlantic) and E. b. nauticus (Pacific) showing structure shaped by Pleistocene ice scapes, including isolation in refugia during glacial maxima and post-glacial dispersal. This recent evolutionary trajectory underscores the species' dependence on seasonal , with demographic bottlenecks linked to mid-Pleistocene transitions around 1 million years ago, preserving adaptive for ice-obligate traits despite ongoing climatic pressures.

Morphology and Physiology

Physical Characteristics

The bearded seal (Erignathus barbatus) is a medium-sized phocid characterized by a robust body, with adults typically measuring 2.1 to 2.7 in from to tail and weighing between 200 and 430 kilograms. Females are generally larger than males, with evident in body size. The heaviest recorded individual was a female weighing 432 kilograms. Bearded seals possess a small, rounded head with a short, thick and a wide, fleshy muzzle. Their foreflippers are short and rounded with robust claws, while the hindflippers are broad and flexible, aiding in through . A distinctive feature is the cluster of coarse, bristly mystacial that curl when dry, numbering up to several hundred and specialized for detecting prey vibrations on the seafloor. The pelage coloration ranges from gray-brown on the back to paler on the sides and underside, often with irregular light patches, providing on . A thick layer of underlies the skin, reaching maximum thickness in winter and early spring for insulation and energy storage in conditions. Pups are born with a natal pelage of dark gray , measuring about 1.3 meters in length and weighing 25 to 35 kilograms at birth.

Sensory and Physiological Adaptations

Bearded seals exhibit specialized tactile sensory adaptations through their mystacial vibrissae, which form large fields on a broad, muscular snout numbering approximately 244 whiskers per side, enabling detection of water movements and prey vibrations for benthic foraging. These vibrissae possess a unique follicle-sinus complex microstructure with dense innervation, facilitating precise tactile discrimination of hydrodynamic trails left by epibenthic prey such as fish and invertebrates on the seafloor. The undulating surface structure of the whiskers minimizes self-induced vibrations during movement through water, enhancing signal-to-noise ratios for flow sensing and reducing sensory noise during hunts in turbid Arctic conditions. Underwater audition in bearded seals demonstrates high sensitivity, with auditory thresholds peaking near 50 dB re 1 µPa across a broad band from approximately 1 kHz to 10 kHz, supporting detection of conspecific vocalizations and environmental cues during submerged activities. Visual adaptations include forward-facing eyes with a for enhanced low-light sensitivity, though specific acuity data for bearded seals remains limited; pinniped corneas and lenses are generally flattened for refractive correction underwater, aiding in prey location amid variable light regimes. Olfactory capabilities are moderate, primarily utilized above water for detecting predators or conspecifics, but less critical during dives due to reliance on other modalities. Physiologically, bearded seals maintain thermal via a thick layer comprising up to 40% of body mass, which insulates against subzero waters and stores energy for prolonged periods; countercurrent exchangers in nasal passages and flippers further minimize conductive loss, with nasal turbinates achieving efficient and moisture retention during exhalation. Diving adaptations include elevated myoglobin concentrations in skeletal muscles for , enabling aerobic dives typically lasting under 10 minutes to depths of 100-200 meters, with an estimated aerobic dive limit around 15-20 minutes before lactate accumulation; and peripheral during submergence preserve oxygen for vital organs. Muscle compositions favor slow-twitch oxidative types, supporting sustained benthic foraging bouts without rapid fatigue, as evidenced by comparative analyses showing bearded seal locomotor muscles with high oxidative capacity relative to other phocids.

Habitat and Distribution

Geographic Range

The bearded seal (Erignathus barbatus) has a circumpolar distribution confined to Arctic and sub-Arctic marine environments, primarily in association with seasonal pack ice. Its range extends latitudinally from the central Arctic Ocean at approximately 85°N southward to about 45°N in the western Pacific Ocean near Hokkaido and Sakhalin Island, and to roughly 55°N in the eastern Atlantic sector around Hudson Bay. This distribution reflects the species' dependence on shallow coastal waters and drifting ice for hauling out, foraging, and breeding, with presence generally limited south of 85°N. In the Pacific Arctic, the Beringia distinct population segment (E. b. nauticus) occupies the Bering, Chukchi, and Beaufort Seas, encompassing areas from the northern northward into the Basin. The nominate subspecies (E. b. barbatus) predominates in the Atlantic , ranging across the , Norwegian, and Barents Seas, as well as the Canadian . Occurrences are patchily distributed, concentrated in regions with suitable ice cover and benthic prey availability, such as the Laptev and East Siberian Seas in the Russian . Vagrants have been documented outside core ranges, including rare sightings in temperate waters like the northern Gulf of Mexico or European coasts, but these do not indicate established populations. The species' range has remained relatively stable historically, though shifts in sea ice dynamics due to climatic variations may influence seasonal occupancy patterns.

Habitat Preferences and Associations

Bearded seals (Erignathus barbatus) primarily inhabit and sub-Arctic marine environments characterized by seasonal , with a strong preference for loose, moving pack ice over shallow waters. They favor areas with water depths generally less than 200 meters, which facilitate access to benthic prey such as bivalves and crustaceans on the seafloor. This depth preference aligns with their foraging behavior, as they dive to the bottom to feed, avoiding deeper offshore waters where suitable substrates are less accessible. The species exhibits a close association with dynamic ice features, including leads, polynyas, and ice edges, where ice concentration is patchy, typically 50-75% cover. These habitats provide platforms for hauling out during whelping, nursing, and molting, while adjacent open water supports hunting and . Bearded seals avoid dense, stable ice packs, which limit mobility and prey access, and instead select drifting ice floes that can extend into deeper waters but remain proximate to shallow zones. In summer, as ice recedes, individuals may shift to coastal rocky shores or persistent land-fast ice for haul-outs, though their primary affinity remains with ice-obligate conditions. Habitat associations extend to coastal regions, but bearded seals are occasionally observed in offshore drifting pack ice far from shore, provided underlying supports their ecological needs. Empirical tracking studies confirm seasonal fidelity to ice-edge habitats, with juveniles showing similar preferences to adults, underscoring the ' dependence on dynamics for survival and reproduction. Variations in ice type and water depth directly influence density estimates, with higher abundances in shallow, intermediate ice cover areas.

Behavior and Ecology

Foraging and Diet

Bearded seals (Erignathus barbatus) are primarily benthic foragers, targeting prey on or near the seafloor in shallow coastal waters, with dives typically averaging less than 40 meters in depth and lasting under a few minutes, though maximum depths can reach 200 meters. They employ specialized vibrissae (whiskers) to detect hydrodynamic trails from prey, enabling precise location of buried or hidden organisms in soft sediments. Foraging occurs mainly during daylight in summer but shifts to nocturnal patterns in winter under ice cover, reflecting adaptations to prey availability and light conditions. Their diet consists predominantly of benthic invertebrates, which comprise over 95% of consumed prey items in stomach analyses from Alaskan populations across multiple decades. Key components include shrimps such as Sclerocrangon borealis (up to 50% of diet volume in some spring samples), clams like Astarte spp., crabs, and whelks, supplemented by infaunal epibenthic organisms. Fish, including Arctic cod (Boreogadus saida), sculpins, and flatfishes, form a secondary portion, often less than 10% by volume but increasing in pelagic forms during periods of reduced sea ice. Cephalopods like squid are occasional prey. Diet composition varies regionally and seasonally; for instance, early spring samples from the near showed shrimp and clams dominating 86% of non-empty stomachs, while pre-partum females in contrasting ice years (2005–2007) shifted toward more benthic in heavier ice conditions and in lighter ice scenarios, indicating opportunistic adjustments to environmental cues. These patterns underscore a generalist strategy resilient to fluctuations in benthic productivity, though sustained ice loss could favor energy-dense over lower-calorie .

Social Structure and Movement

Bearded seals (Erignathus barbatus) exhibit a largely solitary , maintaining distance from conspecifics even in areas of high density outside of the breeding season. They typically haul out individually or in small, loose aggregations on the edges of ice floes, positioning their heads toward open water to facilitate rapid submersion in response to threats. Mother-pup pairs form temporary bonds during the period, with females isolating themselves to care for offspring, after which pups become independent and solitary. During the breeding season in , small groups of up to 50 individuals may congregate on stable ice, where males produce distinctive underwater vocalizations to attract females and defend territories, occasionally leading to agonistic interactions between males. Evidence from satellite telemetry and acoustic monitoring suggests males may employ alternative strategies, including territorial advertisement via calls and nomadic searching, rather than forming stable harems. Movements of bearded seals are primarily driven by seasonal dynamics of sea ice, with which they maintain a close association as a pagophilic species. In the Bering and Chukchi seas, populations undertake predictable migrations: individuals shift southward into the during autumn and winter as pack ice advances, following the ice edge for foraging and resting habitat, then migrate northward into the Chukchi and Beaufort seas in late spring and summer as ice retreats. These patterns result in slower southward displacements focused on , contrasted with faster northward progressions emphasizing ice tracking. Juvenile seals display more exploratory post-weaning, with home ranges expanding to maximum sizes between 31 and 60 days of age before stabilizing, while adults show consistent ice-affiliated ranging with bimodal diving profiles peaking at shallow (<10 m) and mid-depth (50-70 m) bouts. In regions like , year-round tracking reveals variable individual excursions but persistent fidelity to habitats, underscoring vulnerability to accelerated ice loss.

Vocalizations and Communication

Male bearded seals (Erignathus barbatus) produce distinctive underwater trills primarily during the mating season from March to May, serving to attract females and deter rival males in a polygynous breeding system. These vocalizations are among the most prominent in marine soundscapes, with source levels reaching up to 190 dB re 1 μPa at 1 m, enabling detection over distances exceeding 30 km under optimal conditions. Trills consist of narrow-bandwidth, frequency-modulated pulses that descend in pitch, often described as spiraling glissandos, with fundamental frequencies ranging from 200 to 800 Hz and durations of 0.5 to 5 seconds per pulse. Analysis of over 970 recorded trills has identified at least six distinct types based on and temporal features, including ascending, descending, and flat-frequency variants, suggesting variability in signaling intent or individual identity. Vocal activity persists year-round at lower levels outside breeding, potentially for territorial maintenance or social coordination, with acoustic presence correlating to breakup and from shipping or wind. Seals exhibit partial amplitude adjustment in response to ambient noise, increasing call intensity up to a threshold of approximately 110 dB re 1 μPa before ceasing escalation, which may limit effective communication amid anthropogenic or natural acoustic interference. Underwater vocalizations appear linked to alternative mating strategies, as satellite-tagged males producing trills often remain stationary over polynyas while non-vocalizers roam more widely, indicating a trade-off between acoustic advertisement and mate searching. Females and pups produce fewer documented sounds, primarily short moans or growls during interactions on ice, though systematic data remain limited compared to male displays. These vocal patterns underscore the species' reliance on acoustic signaling in visually opaque sub-ice environments, where sound propagation facilitates mate location without physical confrontation.

Reproduction and Life History

Mating Systems and Breeding

Bearded seals (Erignathus barbatus) employ a polygynous in which males compete for access to multiple females through underwater vocal displays and loose territorial defense on or near . Males typically arrive at breeding grounds several weeks prior to females, establishing positions via repetitive trills and other stereotyped vocalizations that serve to advertise availability and deter rivals. Each male produces a unique vocal repertoire, facilitating individual recognition, and many return to the same approximate locations annually to maintain familiarity in unpredictable ice environments. Alternative mating tactics occur among males, with some defending small, discrete territories while others adopt roaming strategies to intercept females without fixed sites, potentially adapting to variable ice conditions that limit centralized leks. Serial may predominate in areas of more stable , allowing paired males to guard females temporarily, though overall prevails due to male-biased operational sex ratios and vocal competition. is strictly aquatic, occurring immediately after females wean their pups in , typically from to depending on , which aligns with post-lactation female receptivity and minimizes energy overlap with pupping demands. Reproductive timing features , with in May-June followed by delayed implantation, resulting in an effective of about 11 months until whelping the next spring. Females attain at 4-6 years, males at 5-7 years, with breeding commencing in winter-early spring when provides platforms for vocal activity, though direct observations remain limited due to the underwater nature of copulation.

Pup Development and Parental Care

Bearded seal pups (Erignathus barbatus) are born on stable sea ice from late March to mid-May, with peak pupping in early May in regions like Svalbard; they measure approximately 1.3 meters in length and weigh 33–37 kg at birth, covered in a greyish lanugo coat that is shed during the nursing period. Females provide exclusive parental care, as males depart after mating and contribute nothing to pup rearing; mothers remain attentive, nursing pups for 18–24 days while fasting and losing significant body mass. During , pups consume about 8 liters of high-fat daily, achieving a growth rate of approximately 3.3 kg per day and reaching 80–124 kg by , primarily as accumulation for post-weaning fasting and . Pups enter the water within a week of birth, developing diving proficiency under maternal supervision, with mothers guiding them in short aquatic excursions that increase in duration and depth; this ontogenetic shift prepares them for independent , as pups begin capturing prey like and before . Upon , mothers abruptly abandon pups, who then haul out on to fast while honing skills, relying on accumulated reserves for survival until self-sufficient; this post-weaning period lasts several weeks, during which pups disperse and face high predation risks from and orcas. Females typically ovulate and remate within two weeks of weaning, initiating delayed implantation for the next reproductive cycle.

Lifecycle Stages and Longevity

The bearded seal lifecycle begins with mating in late spring or early summer, followed by delayed implantation of the blastocyst for approximately 2-2.5 months, resulting in an effective gestation period of about 11 months. Pups are born on stable sea ice from March to May, with peak birthing in April, typically weighing 30-40 kg and measuring 120-130 cm in length. During the pup stage, mothers provide intensive for 18-24 days, during which pups gain weight rapidly to 85-117 kg at , while the fasts and loses significant body mass. Pups enter the water within hours of birth, developing and diving abilities quickly; by one week old, they can submerge, and by six weeks, they achieve dives exceeding 488 m. occurs around late May to June, after which pups become independent, foraging solitarily and dispersing distances of 40-550 km, though post-weaning survival is low with pup mortality rates up to 60%. Juvenile bearded seals exhibit rapid growth, increasing in length by 26% in the first year and 12-15% in the second, slowing to less than 4% annually thereafter, reaching dimensions of 2.1-2.5 and 200-430 kg by 5-7 years. is attained by females at 5-6 years and males at 6-7 years, marking the transition to reproductive hood where annual breeding cycles resume. Longevity in bearded seals averages 20-25 years, with maximum recorded ages of 30-31 years based on tag recoveries and age determinations from harvested individuals. Survival improves after the first year, when rates drop from 19% to higher levels into adulthood, reflecting to and ice-dependent habitats.

Conservation and Human Interactions

Population Dynamics and Status

The bearded seal (Erignathus barbatus) is classified as Least Concern globally by the , reflecting a population that is not currently facing imminent extinction risk despite vulnerabilities to environmental changes. However, the distinct population segment (DPS), spanning the Bering and Chukchi Seas, has been listed as threatened under the U.S. Endangered Species Act since 2012 due to projected habitat loss from decline. Similarly, the Okhotsk Sea DPS is considered threatened under foreign provisions of the ESA. Global abundance is estimated at 500,000 to 1,000,000 individuals, though precise counts remain unavailable owing to challenges in surveying vast and sub-Arctic ranges. Regional surveys provide partial insights; for instance, approximately 147,000 bearded seals inhabit the , based on 2013 aerial and underwater acoustic data adjusted for detection biases. In the Pacific , populations of ice-associated seals, including bearded seals, are described as large and healthy as of 2024, with no observed long-term declines in body condition despite shifting prey availability linked to warming. Population trends are data-poor overall, with limited reliable time-series for most regions; available evidence indicates stability rather than significant decline. Pup growth rates near have remained consistent since 2006 amid sharp reductions, suggesting behavioral adaptations such as increased use of fronts for hauling out. Demographic modeling from harvested samples in estimates finite rates near replacement (λ ≈ 1.0), supporting sustainable subsistence harvests of 1,500–2,000 individuals annually without detectable . Climate-driven loss poses the primary long-term risk, potentially elevating mortality through reduced breeding habitat, though current projections do not indicate imminent collapse.

Threats and Environmental Pressures

The primary environmental pressure on bearded seals (Erignathus barbatus) is the ongoing loss of driven by warming. These seals require stable, annual over shallow waters (typically less than 200 meters deep) for hauling out, molting, pupping, and accessing benthic prey such as clams and crabs; projections from models forecast a continued decline in extent, duration, and thickness, with summer potentially absent in the by mid-century under moderate emissions scenarios. This degradation disrupts breeding by causing earlier breakup, which shortens the period for pups (normally 8-12 days) and exposes them to predation and , potentially reducing recruitment rates by 20-50% in affected regions based on observed trends in -associated seals. In response to these pressures, the IUCN Red List assessed the bearded seal as Near Threatened in its October 2025 update, elevating it from Least Concern primarily due to sea ice erosion threatening core populations in the Bering, Chukchi, and Okhotsk Seas. In the U.S. Pacific sector, the Beringia and Okhotsk distinct population segments were listed as threatened under the Endangered Species Act in 2012, with habitat loss identified as the foremost risk factor over direct anthropogenic mortality. Associated ecological shifts include altered prey distribution—favoring pelagic fish over bottom-dwelling invertebrates—and increased competition from sub-Arctic species migrating northward, further straining foraging efficiency. Secondary threats include bioaccumulative contaminants such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (), and , which enter food webs via long-range atmospheric transport and persist in seal and tissues at levels that may impair immune function and reproduction, though empirical evidence links these primarily to sublethal effects rather than population-level declines. Emerging pressures from expanded shipping and industrial activities in lengthening open-water periods introduce underwater noise and vessel strikes, potentially elevating and displacing seals from traditional polynyas, but these remain subordinate to loss in assessments.

Subsistence Hunting and Management

Subsistence hunting of bearded seals (Erignathus barbatus) is conducted by indigenous coastal communities across the , including from to Kaktovik and hunters in areas like Utqiaġvik, who harvest the seals for meat, oil used in and , and hides for traditional skin boats (umiaqs) essential for spring and other activities. typically occurs during the open-water from late through , when seals haul out on shore or are accessible from boats, though retreating has shortened effective periods by approximately one day per year over the past 17 years in some regions. Reported annual subsistence harvests in communities during 2009–2013, compiled by the Ice Seal Committee, ranged from dozens to hundreds per community, reflecting low overall take relative to estimated population sizes exceeding 300,000 in the region. In , bearded seal harvest management is co-administered by the (NMFS) and the Alaska Native Ice Seal Committee under federal subsistence priority guidelines, permitting unlimited take by qualified rural residents without species-specific quotas, as subsistence levels are deemed sustainable and non-commercial. The distinct population segment (E. b. nauticus) was designated threatened under the U.S. Endangered Species Act on December 28, 2012, primarily due to projected sea ice loss from , yet regulations explicitly allow continued indigenous subsistence hunting alongside conservation measures like critical habitat designation finalized in 2022. No significant commercial harvest occurs, and historical data indicate subsistence pressure remains minimal compared to environmental threats. Across broader Arctic ranges, including and , subsistence hunting proceeds without quotas, with Canadian Inuit communities harvesting an estimated 3,000–5,000 seals annually from the late to mid-1980s across 46 communities, and similar unregulated practices persisting today as a key protein source. The North Atlantic Marine Mammal Commission (NAMMCO) provides management advice but notes no international regulatory body enforces quotas, emphasizing monitoring to ensure harvests do not impede recovery amid climate-driven declines. In Norwegian waters, including , sport and subsistence hunting occur without set quotas under the Marine Resources Act, following historical reductions from quotas in the 1970s–1980s that limited catches to a few thousand annually.

References

  1. https://nammco.no/bearded-seal/
  2. https://animaldiversity.org/accounts/Erignathus_barbatus/
  3. https://www.adfg.alaska.gov/index.cfm?adfg=beardedseal.printerfriendly
  4. https://www.adfg.alaska.gov/static/education/wns/bearded_seal.pdf
  5. https://iucn.org/press-release/202510/arctic-seals-threatened-climate-change-birds-decline-globally-iucn-red-list
  6. https://www.fisheries.noaa.gov/species/bearded-seal
  7. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.103659/Erignathus_barbatus
  8. https://www.fws.gov/taxonomic-tree/32177
  9. http://www.marinespecies.org/aphia.php?p=taxdetails&id=137079
  10. https://www.sciencedirect.com/science/article/abs/pii/S1055790304001940
  11. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=39304
  12. https://animalia.bio/bearded-seal
  13. https://media.fisheries.noaa.gov/dam-migration/2019_sars_alaska_bearded_seal.pdf
  14. https://www.pinnipeds.org/seal-information/species-information-pages/the-phocid-seals/bearded-seal
  15. https://media.fisheries.noaa.gov/2021-08/BEARDED-SEAL-Erignathus-barbatus-nauticus-Beringia-Stock.pdf
  16. https://pmc.ncbi.nlm.nih.gov/articles/PMC6548721/
  17. https://pmc.ncbi.nlm.nih.gov/articles/PMC7735288/
  18. https://www.sciencedirect.com/science/article/abs/pii/S1055790306001977
  19. https://www.researchgate.net/publication/8375120_A_phylogeny_of_extant_Phocidae_inferred_from_complete_mitochondrial_DNA_coding_regions
  20. https://academic.oup.com/evolut/article/76/6/1260/6728819
  21. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/06-0624.1
  22. https://www.jstor.org/stable/1380731
  23. https://www.researchgate.net/publication/298790621_Notes_on_past_and_present_distribution_of_the_Bearded_seal_Erignathus_barbatus_around_the_North_Atlantic_Ocean
  24. https://www.authorea.com/users/804381/articles/1191930-circumpolar-population-structure-diversity-and-recent-evolutionary-history-of-the-bearded-seal-in-relation-to-past-and-present-icescapes
  25. https://pubmed.ncbi.nlm.nih.gov/39835612/
  26. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/bearded-seal
  27. https://www.adfg.alaska.gov/index.cfm?adfg=beardedseal.main
  28. https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=3731&context=theses
  29. https://pubmed.ncbi.nlm.nih.gov/16342212/
  30. https://pmc.ncbi.nlm.nih.gov/articles/PMC3172597/
  31. https://www.researchgate.net/publication/343923399_Auditory_biology_of_bearded_seals_Erignathus_barbatus
  32. https://www.sciencedirect.com/science/article/pii/S0022519324002182
  33. https://sicb.org/abstracts/physiological-adaptations-for-diving-in-the-bearded-seal/
  34. https://www.aquaticmammalsjournal.org/wp-content/uploads/2024/04/50.3_Tengler.pdf
  35. https://www.fisheries.noaa.gov/action/designation-critical-habitat-beringia-distinct-population-segment-bearded-seal
  36. https://www.mmc.gov/wp-content/uploads/21-04-08-Kurland-NMFS-Bearded-seal-critical-habitat.pdf
  37. https://pmc.ncbi.nlm.nih.gov/articles/PMC5830299/
  38. https://link.springer.com/article/10.1007/s00300-023-03200-1
  39. https://www.nature.com/articles/s41598-018-35306-6
  40. https://www.adfg.alaska.gov/static/research/programs/marinemammals/pdfs/biology_bearded_seal.pdf
  41. https://www.jstor.org/stable/40511532
  42. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038307
  43. https://pmc.ncbi.nlm.nih.gov/articles/PMC3365033/
  44. https://nhpbs.org/natureworks/beardedseal.htm
  45. https://www.sciencedirect.com/science/article/pii/S0003347203920483
  46. https://www.kotzebueira.org/environmental-projects/2009-2012-adult-bearded-seal-project/
  47. https://research-repository.st-andrews.ac.uk/handle/10023/18636?show=full
  48. https://link.springer.com/article/10.1007/s003000000121
  49. https://www.sciencedirect.com/science/article/abs/pii/S0967064522002016
  50. https://link.springer.com/article/10.1007/s00300-021-02874-9
  51. https://marinemammalscience.org/facts/erignathus-barbatus/
  52. https://cdnsciencepub.com/doi/10.1139/z89-272
  53. https://www.researchgate.net/publication/238018061_Underwater_vocalizations_of_the_bearded_seal_Erignatus_barbatus
  54. https://link.springer.com/article/10.1007/s00300-013-1337-1
  55. https://pmc.ncbi.nlm.nih.gov/articles/PMC7934916/
  56. https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.12732
  57. https://dosits.org/galleries/audio-gallery/marine-mammals/pinnipeds/bearded-seal/
  58. https://pmc.ncbi.nlm.nih.gov/articles/PMC11549065/
  59. https://apps-afsc.fisheries.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-211.pdf
  60. https://rep.bioscientifica.com/view/journals/revreprod/2/3/175.pdf
  61. https://www.wildlifenorthamerica.com/Mammal/Bearded-Seal/Erignathus/barbatus.html
  62. https://npolar.no/en/species/bearded-seal/
  63. https://onlinelibrary.wiley.com/doi/10.1111/mms.12647
  64. https://www.researchgate.net/publication/336353915_Bearded_seal_Erignathus_barbatus_birth_mass_and_pup_growth_in_periods_with_contrasting_ice_conditions_in_Svalbard_Norway
  65. https://www.int-res.com/abstracts/meps/v627/meps13072
  66. https://cdnsciencepub.com/doi/10.1139/as-2024-0068
  67. https://arctic.noaa.gov/report-card/report-card-2024/ice-seals-of-alaska/
  68. https://accs.uaa.alaska.edu/wp-content/uploads/erignathus_barbatus_nauticus.pdf
  69. https://www.climate.gov/news-features/featured-images/2024-arctic-report-card-ice-seal-populations-pacific-arctic-remain
  70. https://www.mmc.gov/wp-content/uploads/IceSealsHabitatLoss_MCameron.pdf
  71. https://www.fisheries.noaa.gov/national/climate/seals-sea-lions-and-climate-change-shifting-prey-and-habitat-impacts
  72. https://news.mongabay.com/2025/10/arctic-seals-edge-closer-to-extinction-as-sea-ice-vanishes/
  73. https://lamont.columbia.edu/news/scientists-and-native-people-jointly-study-sea-ice-declines-threatening-seal-hunts
  74. https://www.federalregister.gov/documents/2010/12/10/2010-30931/endangered-and-threatened-species-proposed-threatened-and-not-warranted-status-for-subspecies-and
  75. https://www.adfg.alaska.gov/index.cfm?adfg=beardedseal.uses
  76. https://www.lenfestocean.org/en/research-projects/indigenous-knowledge-habitat-models-of-bearded-seals-ugruk-erignathus-barbatus
  77. https://www.arcticwwf.org/the-circle/stories/retreating-sea-ice-threatens-indigenous-way-of-life/
  78. https://downloads.regulations.gov/BOEM-2017-0050-51354/attachment_112.pdf
  79. https://www.adfg.alaska.gov/index.cfm?adfg=beardedseal.management
  80. https://www.fisheries.noaa.gov/feature-story/new-method-provides-reliable-estimates-bearded-seals
  81. https://www.federalregister.gov/documents/2022/04/01/2022-06173/endangered-and-threatened-species-designation-of-critical-habitat-for-the-beringia-distinct
  82. https://www.north-slope.org/wp-content/uploads/2022/04/Proposed-listing-for-Bearded-Seals-10-Dec-2010.pdf
  83. https://hero.epa.gov/hero/index.cfm/reference/details/reference_id/4964868
  84. https://par.nsf.gov/servlets/purl/10182361
  85. https://nammco.no/wp-content/uploads/2023/07/bsws-final-report-july-31st.pdf
Add your contribution
Related Hubs
User Avatar
No comments yet.