The ribbon seal (Histriophoca fasciata ) is a medium-sized pinniped from the true seal family (Phocidae). A seasonally ice-bound species, it is found in the Arctic and Subarctic regions of the North Pacific Ocean, notably in the Bering Sea and Sea of Okhotsk. It is distinguished by its striking coloration, with two wide white strips and two white circles against dark brown or black fur.
It is the only living species in the genus Histriophoca, although a possible fossil species, H. alekseevi, has been described from the Miocene of Moldova.
The Ribbon seal is a medium-sized pinniped from the true seal family. The adult coat has a dark background encircled with four light-colored stripes. One stripe goes around the neck and around the mid-rear section of the seal's body, the others start ventrally and go around the fore flippers on each side. Although all Ribbon seals have this general pattern, there is great individual variability regarding the precise location and the shade of the stripes. Babies and juveniles do not have such a pattern, newborns being completely white, and juvenile seals dark dorsally and anteriorly, and grayish ventrally and posteriorly. Males are usually darker than females. Ribbon seals have big eyes and small teeth.
Ribbon seals live in the subarctic and Arctic and parts of the North Pacific Ocean, notably in the Sea of Okhotsk and the Bering Sea, near southern Russia, to the north of Japan and Korea. These seals spend most of their life in cold waters, preferring deeper waters. It is rare to see them on land. They seem to favor fairly thick, stable, clean, new white ice floes which have even surfaces.
Ribbon seals forage for food at night. They are usually solitary but sometimes form small groups. Most of their time they spend in the water foraging or moving between the breeding areas and areas with lighter sea ice. During the mating season, seals of every age, gender, and size are found together. Mating and molting seasons overlap, both taking place during the ice breakup in the spring. Adults come to the ice to breed, and juveniles use it as a site where they can molt. When these seals feel threatened, they visually scan the area for much longer than other pinnipeds. It is believed that poor eyesight when they are out of water is the reason for this time spent scanning. Ribbon seals do not seem concerned by the threat of predators, allowing their young to wander some distance from their mother for a long period of time. They rear their young on thinning ice, which forms a barrier for many of their predators.
Ribbon seals are carnivores (piscivores). As juveniles, they feed mainly on shrimp as well as other small crustaceans. Adult seals eat cephalopods, crustaceans, and fish.
Ribbon seals are polygynous, with one male mating with multiple females. Male ribbon seals use their air sac for vocalizations during mating, both to establish or defend territories and to attract mates. The breeding season is from May to June, with mating centering around the breakup of ice every spring. The gestation period is about 11 months, and a single pup is born, usually in April. Birth takes place on pack ice. They nurse their pups for between four and six weeks. At weaning, mothers help their pups become independent by showing them how to dive for food. Females become reproductively mature at 2-5 years of age, while males start to breed when they are 3 to 6 years old.
The biggest threat to these animals is climate change as a result of global warming, which may affect distributions of polar ice. Other threats include human impacts from oil spills, annual harvests and by-catch.
According to the NMFS (NOAA), the global population of Ribbon seals is 240,000, and 90,000-100,000 of these inhabit the Bering Sea. On the IUCN Red List. this species is currently classified as Least Concern (LC).
