The largest populations are in the Bering or Okhotsk seas. Phoca fasciata are commonly known as ribbon seals, reflecting the markings of their coat. The adult coat of a ribbon seal is most easily described as a dark background with four light colored stripes running in a circle around the animal. One stripe encircles the neck, another encircles the mid-posterior portion of the seal's body, and the other two stripes start ventrally and encircle the foreflippers on either side. Although this is the general pattern for all ribbon seals, there can be great individual variability as to the shade and precise location of the stripes.
Males tend to be darker than females.
Other ribbon seal traits include large eyes and small teeth. An adult P. fasciata will grow to about 1.6m and weigh 70kg, and has a lifespan of about 20 years. Ribbon seals also eat squid, shrimp, and crabs. Juvenile seals have been reported to eat a lare proportion of crustaceans. May. Typically ribbon seals give birth to one pup with the birthing occurring on ice flows.