General Description

Bearded seals belong to the suborder Pinnipedia and the family Phocidae (true seals). They are the largest northern phocid seal. There are two subspecies of the bearded seal. E. barbatus barbatus is found in the western Laptev Sea, the Barents Sea, and the North Atlantic Ocean while E. barbatus naticus inhabits the remainder of the Arctic Ocean, the Bering, Chukchi, and Okhotsk Seas, and the northern Pacific Ocean. (Seal Conservation Society, 2001). Also, the name bearded seal comes from their numerous long whiskers which curl up when dry (Burns 1967). Bearded seals are variable in color from tawny-brown to silver-gray and are generally darker down the back, but have no spots or bands (Burns, 1967). They also lack dense fur so they rely on a heavy layer of fat for warmth (Rearden, 1981).


Bearded seals can be 7.5-8 feet from nose to tail and females can be slightly larger than males. Their weight and condition is variable throughout the year because adults can loose up to 30% of their weight between January and June, mostly from reduction of the blubber layer (Burns, 1967). These seals weigh about 750 lbs in winter and 475 to 525 lbs in summer. To correlate bearded seals' weight with their annual life history events, bearded seals are the fattest before the reproduction events and lactation and they're leanest right after the period of molting (Anderson et al. 1999). The period of molting is usually followed by a period of intensive feeding as seals rebuild their energy stores and blubber for the winter (Anderson et al. 1999). Also, bearded seals can live between 20 and 23 years in the wild (Rearden, 1981).

Image courtesy of Hugh Harrop www.hughharrop.com

Feeding
Bearded seals are benthic feeders, mostly feeding on invertebrates from the sea floor. They eat shrimp, crab, bottomfish, octopus, worms, clams, and tunicates (Rearden, 1981). A study by Hjelset et al. (1999), which investigated the bearded seal population in Svalbard, Norway, found fish to be the most important group of prey for bearded seals, followed by crustaceans and then mollusks. This study also found that individual seals eat a wide variety of prey organisms and that there was no significant difference in prey choices between the sexes. But, another study found that bearded seals in the Fram Strait occupy the pack-ice area over water that is about 3000m deep, which may indicate that some bearded seals can feed on the sympagic (ice associated) community of organisms (Dietz et al. 1985 as cited in Gjertz et al. 2000). Bearded seals do not have a lot of competition for food, except sometimes from other seal species and from commercial fisheries (Seal Conservation Society, 2001).

Haul-out behavior
Bearded seals are almost completely aquatic, but do haul-out on edges of wide leads, holes in the ice, or the points of small ice floes, probably because such sites offer a multidirectional view and a quick means of escape (Kingsley and Stirling, 1991). When hauled-out, bearded seals immediately turn around and face both the water and downwind, so that they can escape quickly into the water with minimal movement (Kingsley and Stirling. 1991). Seals probably haul-out to rest or for mothers to give birth or nurse. But the nature of sleeping and resting is very little understood in the bearded seal. Sleeping at sea could be energetically costly because bearded seals are negatively buoyant (Harrison et al. 1968). Stirling and Thomas (2003) suggested that haul-out behavior was probably indicative of a period of evolutionary history without terrestrial predators.
  Bearded seal pup hauled-out on ice floe. Image courtesy of NOAA. Photographer: Lew Consiglieri, NOAA Corps. Taken June 1978.
Predation
Some studies reported that bearded seals have low to medium levels of predation from polar bears (Ursus maritimus) (Stirling and Thomas, 2003), but others reported that predation pressure from polar bears is high (Lydersen and Kovacs, 1999). Predation of bearded seals occurs most often in pack ice when the seals are hauled-out and bears kill mainly newborn young (Smith, 1980). From evidence from scars on bearded seals, Smith (1980) concluded that polar bear predation could be a significant morality factor in the bearded seal in at least some parts of the arctic. But this scar evidence is debatable, because other researchers believe that at least some of the scar marks found on bearded seals are from intraspecific fighting (Smith, 1980). Polar bear predation affects the bearded seal’s haul-out behavior by affecting their choice of haul-out sites and position on the ice (Kingsley and Stirling, 1991). Other possible predators of the bearded seal include killer whales (Orcinus orca) and Greenland sharks (Somniosus microcephalus) (Lydersen and Kovacs, 1999).
The final predator of the bearded seal is humans. For a long period of time seals have been hunted by arctic coastal communities for food, clothing and other purposes. In the Bering and Okhotsk Seas, Russian hunters have taken up to 1,500-2,000 seals per year in the past, but probably take less today (Seal Conservation Society, 2001). Bearded seals are also hunted by the natives of Alaska, Canada, Iceland, Greenland, and the Norwegian Svalbard area (Seal Conservation Society, 2001).