(Schreber, 1775) -Ringed seal
Ringed seals resemble harbour and Larga seals, but are decidedly plumper (axillary girth may reach 80% of length). They also have a smaller, somewhat rounded head, and a conspicuously short and thick neck. The muzzle is short, slightly broader than thick, and blunt. The vibrissae are light-coloured and beaded. The eyes are relatively large and conspicuous. More than in other northern phocids, the size of the head and muzzle and close-set, forward-facing, eyes impart a cat-like appearance. The foreflippers are relatively small and slightly pointed, as described for the harbour seal.
Coloration is the most distinctive feature. Ringed seals are conspicuously marked with spots that, especially on the back and sides, are circled with rings of lighter colour. The spots are the same colour as, or slightly darker than, the background colour of the coat. The rings are light grey to off-white. Seals can be so heavily marked that many spots and rings fuse. Despite individual and regional variation in both species, ringed seals are usually more profusely covered with ringed spots than are harbour seals. There are generally no, or very few, spots on the undersides, a feature that distinguishes ringed seals from both harbour and Larga seals. The background coloration is variable, but normally medium to dark grey above and light grey to silver below. Pups are born with a woolly thick whitish lanugo. Fur of the succeeding coat is finer and slightly longer than that of adults, and is dark grey above, merging to silver below. There may be a few scattered dark spots on the undersides of these juveniles, and few, if any, rings on the back. At this stage, they are known as “silver jars”.
The dental formula is I 3/2, C 1/1, PC 5/5.
Can be confused with
Ringed seals share their extensive range with 7 other phocids. They are not likely to be confused with bearded, harp, hooded, or ribbon seals, but care may be required to positively distinguish them from other seals with rings, spots or spot-like markings (harbour, Larga, juvenile harp, and Grey seals). Differentiation requires attention to the size, coarseness, distribution (both above and below), and abundance of such markings. Also, note head and muzzle size, body length, and plumpness and length of the neck in relation to the body length.
Adults are up to about 1.65 m in lenth. Weight is 50 to 110 kg. Pups average about 60 to 65 cm and 4 to 5 kg at birth.
Ringed seals have a circumpolar distribution throughout the Arctic basin, Hudson Bay and Strait, and the Bering and Baltic seas. There are 5 recognized subspecies: P. h. hispida, in the Arctic basin; P. h. ochotensis, in the Seas of Okhotsk and Japan; P. h. saimensis, in Lake Saimaa; P. h. lagodensis, in Lake Ladoga; and P. h. botnica, in the Baltic Sea. The distribution of ringed seals is strongly correlated with pack and land-fast ice, and areas covered at least seasonally by ice.
Biology and Behaviour
Nearly all ringed seals breed on the fast ice, where females excavate lairs in pressure ridges and other snow-covered features. These allow access to the water, but are hidden from polar bears. Pupping generally occurs in March-April, earlier in the Baltic Sea. Males are thought to be territorial, and possibly annually monogamous.
Many adults remain in the same localized areas year-round. Out of water, ringed seals are generally wary, regularly scanning for predators, such as polar bears and humans.
Ringed seals consume a wide variety of small prey, including many species of fishes and planktonic crustaceans, taken throughout the water column. They forage either singly or in small groups.
Ringed seals have been a mainstay in the diet of native Arctic peoples. The seals are consumed by people and fed to sled dogs, and their skins are used for clothing. Subsistence hunting continues today, and accounts for an unknown, but probably significant number of seals every year. Commercial sealing primarily for pelts has been wide-spread. Pollution in some localities, such as the Baltic Sea, is of great concern and may be the reason for local population declines. The status of the current worldwide population is variable, depending on location, with numbers in some areas increasing and decreasing in others.
Insufficiently known; endangered (P. h. saimensis only); vulnerable (P. h. botnica and P. h. lagodensis only).