General description: Ringed seals are the smallest of all pinnipeds (seals, sea lions, and walruses) with adults in Alaska rarely exceeding 5 feet (1.5 meters) in length and 150 pounds (68 kg) in weight. Ringed seals weigh the most in the winter and early spring when they have a thick layer of blubber under their skin. The blubber serves as insulation and as an energy source during the breeding and pupping season. The weight of ringed seals declines with the decrease in feeding during the reproductive and molting season.

The coloration of ringed seals is quite variable, but the basic pattern is a gray back with black spots and a light belly. The seal gets its name from the black spots ringed with light marks.

 

Food habits: Ringed seals eat a variety of invertebrates and fish. The particular species eaten depends on availability, depth of water, and distance from shore. In Alaska waters, the important food species are arctic cod, saffron cod, shrimps, and other crustaceans.

 

Life history: Females give birth to a single, white-coated pup in snow dens on either landfast or drifting pack ice during March and April. Female seals build lairs in pressure ridges or under snowdrifts for protection from predators and severe weather. There is some evidence that females lacking maternal experience give birth in marginal habitat—drifting pack ice—and may be more subject to polar bear predation. More experienced females give birth in the better habitat—landfast ice—and may have higher reproductive success.

The average weight of pups at birth is 10 pounds (4.5 kg). Females nurse pups for about two months and during that time the pup doubles its birth weight. Increasing blubber thickness provides the pup with insulation to reduce heat loss and an energy reserve to use while it learns to find its own food. Weaning usually takes place at ice breakup.

Most females breed again within a month after the birth of the pup. Implantation of the embryo is delayed until mid-July or early August. Pregnancy lasts about 11 months. Most female ringed seals first ovulate at 5 or 6 years of age and first give birth at 6 to 8 years old. Males become sexually mature at the same age.

 

Migration and distribution: Ringed seals generally occur in association with sea ice; however, some ringed seals are seen during ice-free periods in the Bering and Chukchi seas. Seals appear at various coastal locations with the formation of shorefast ice in the fall. They disappear in the spring with the ice breakup. Seals wintering in the Bering Sea probably summer in the northern Chukchi Sea or Arctic Ocean. The density of ringed seals varies greatly with the area and the season. In addition to humans, predators of ringed seals include polar bears (the chief predator), arctic and red foxes, walruses, dogs, wolves, wolverines, and ravens. Arctic foxes and polar bears can locate seal lairs by their smell. During pupping, they enter the lairs in an effort to kill and eat the pups.

 

Behavior: Ringed seals emit several types of vocalizations underwater which are not readily audible above water. The function of these calls in unknown. The behavior of ringed seals is poorly understood since both males and females spend the greater part of the year in lairs or in the water. Ringed seals molt in May and June. During this time they spend long periods hauled out on the ice “basking” in the sun. It is thought that warmer skin temperatures cause the new hair to grow more quickly. When hauled out on the ice, ringed seals are very wary, raising their heads every 20 seconds or so to look around. They rapidly enter the water when they detect an approaching human or other predator. Male ringed seals may be territorial during the breeding season.