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Pinnipednesday - Histriophoca fasciata Edition

Twinkle lights are GO, people. Including a new set of flashing snowflakes.

The Ribbon Seal (Histriophoca fasciata) can be found in the northern Pacific Ocean, specifically the Sea of Okhotsk and the Bering Sea. There have been only two recorded instances when a Ribbon Seal was observed south of its usual range, with one sighting near Seattle, Washington and another in Morro Bay, California. It is easy to identify because of its distinctive coat pattern, which is dark brown or black with wide white circle stripes around its neck and body.


Ribbon Seals are medium-sized pinnipeds, and adult males and females are roughly the same size. They can grow up to 5.2 feet (1.6 meters) long and weigh 209 pounds (95 kg). Ribbon Seals are the only extant pinniped that have internal air sacs that are connected to their trachea, running along their right sides over the rib cage. The function of this air sac is not precisely known, although researchers theorize that males (who have larger air sacs than females) will use them to aid in underwater vocalizations.

The diet of the Ribbon Seal consists primarily of pelagic creatures like pollock, octopus, cod, squid and eelpouts. Young Ribbon Seals will feed on crustaceans closer to shore as well. Ribbon Seals are generally solitary animals - they do not form groups the way other pinniped species do. It uses the pack ice present during the winter and spring to haul out and breed, mate, and molt. During the rest of the year, they live in open water.


The breeding season of the Ribbon Seal occurs during April and May, after the females have given birth to that year's pups. The pups are nursed for four weeks, gaining nutrients and fat from their mother's milk. Then they are left on the ice to fend for themselves while they shed their light natal coats. Once their new coats grow in, they are able to enter the water and start learning to hunt.


Because of the Ribbon Seal's solitary nature, they are not as easy to hunt as other pinnipeds, and their overall population did not suffer as much of a loss during the period when many pinnipeds were hunted to the brink of extinction. They currently number about 250,000. Its natural predators include orcas, polar bears and sharks. They are listed as a species of concern by the U.S. National Marine Fisheries Service, because they depend on the pack ice for survival - which is impacted by climate change.


Sources (1, 2, 3, 4, 5) for all images used in this post.

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