Seals

seal_512x219

 Spotted seals, harbor seals, ribbon seals, ringed seals, and bearded seals have all been documented on Togiak Refuge. Harbor seals and spotted seals are common; the other species are rare on Togiak Refuge.

  • Marine Mammals

    Marine mammals spend all or the majority of their time in water, and thus are specially adapted to this way of life. Their thick layers of fat help to keep them warm in frigid waters. Since they are mammals, they must always come up to the surface to breathe, although they can often hold their breath for surprising lengths of time.

  • True Seals (Phocidae)

    harborseal_IMG0536_150x118

    The Phocidae, or true seals, lack external ear flaps and do not use their flippers to "walk" on land. Togiak Refuge is home to five species from this group; the harbor seal and spotted seal are seen fairly frequently, while the ringed seal (Pusa hispida), ribbon seal (Histriophoca fasciata) and bearded seal (Erignathus barbatus) are less common. 

    Groups of seals hauled out around Togiak Refuge may include both harbor seals and spotted seals, since the ranges of the two seals overlap. The two species are quite similar externally and are difficult to distinguish from one another. For many years, spotted seals were regarded as a subspecies of the harbor seal. They are now classified as separate species for a number of reasons. 

    Spotted seals differ from harbor seals (pictured left) in that their pups are born with a soft, light coat while harbor seal pups usually have the same coat as adults. Breeding and pupping occur at different times in the two species. Morphological differences such as skull characteristics also separate the two species.
     

  • Harbor seal (Phoca vitulina

    harborseal_sue_matthes_150x118

    Two distinct color variations of harbor seals exist. The lighter variety have white to silver coats with dark spots; the darker variety have dark gray to brown coats with light rings. Various combinations of color, spots, and types of rings exist. Males may weigh up to 300 pounds and be more than 6 feet in length, with females somewhat smaller.

    Harbor seals typically haul out on intertidal ledges, isolated beaches, mud flats, and sea ice. Their use of haulouts is greatly affected by human disturbance. Humans, dogs, or noise may cause seals to leave a haulout, sometimes permanently, occasionally leaving young behind. Harbor seals haul out in groups, a practice which allows them to rest more and spend less time scanning for predators than if they were alone.

    Harbor seals are known to feed on a wide variety of foods, varying throughout their range, probably dictated by availability. Prey includes fish, cephalopods, crustaceans, octopus, and eels. 

    Seals have larger eyes and better eyesight than their cousins the walrus, since vision aids in obtaining food and avoiding predators. Killer whales, Steller sea lions, eagles, and foxes may prey on harbor seals, especially pups. Hunters from local villages utilize seals as a food source as well.

    Pupping seasons vary throughout the harbor seals' range; pups in the Bristol Bay area are born in June and July. Usually only a single pup is born. They are able to swim within a few hours of birth, which is necessary since they are often born on haulouts that are underwater during high tide. 

    Pups are usually born with the same coloration and hair type as adults. Mothers recognize their pups by their barks. Nursing continues for an average of 4 weeks, with mating following a few days after weaning.

  • Spotted seal (Phoca largha)

    spotted_seal_pup_150x118

    Spotted seal pups, like the one pictured at left, are born with a soft, light-colored coat. The coat of adult spotted seals is usually a dark gray mantle over a lighter brownish or silvery base. Small dark spots are found all over, especially on the back and sides. Adult spotted seals can weigh up to 270 pounds and be more than 5.5 feet long.

    Spotted seals eat fish, cephalopods, crustaceans, octopus, and eels. Predators include human hunters, killer whales, Steller sea lions, eagles, and foxes. Spotted and harbor seals feed on similar species, but in areas where they overlap, they are thought to specialize on different prey items.

    seal pup, spotted. USFWS.Different pupping and breeding times are among the factors that distinguish spotted seals from harbor seals. Pups are born on ice flows, from late January through mid-April, and they usually spend their first several weeks on the ice. 

    Spotted seals form family groups on the ice during breeding season. A male attends to a female during the birth of her pup. The male and female will mate after the pup is weaned 2 to 3 weeks later. Mating pairs do not stay together from season to season.

  • Resources

    Reeves, Randall R. et al. 1992. The Sierra Club handbook of seals and sirenians. Sierra Club Books. San Francisco California.