Sunday, June 6, 2010

Harbor Seal

Our final Alaska Week animal will be one of my favorites - the Harbor Seal. Like some of our other Alaskan friends, Harbor Seals, also known as Common Seals, can be found in other locations. In fact, they exist on the Northern Hemisphere coats of the both the Atlantic and Pacific Oceans. Harbor Seals are abundant in Alaska, numbering over 150,000. This is a substantial amount when the entire Pacific population is only around 300,000.

Taxonomically, Harbor Seals (Phoca vitulina) are considered True or Eared Seals, and are members of family Phocidae. This differentiates them from the fur seals and sea lions (Otariids or Eared Seals) with whom they share the overall Pinniped super family. True Seals have no external ears, dense, short hair, internal or retractable reproductive organs, and are better suited to ocean swimming and endurance than the Eared Seals, though they trade off is a definite awkwardness on land.

Image from Seal Sitters
Harbor Seals can dive to depths of 1640 feet and hold their breath for over 20 minutes. Males are slightly larger than females, reaching 6.5ft as opposed to 5.5. They feed on fish, squid and octopi, and they in turn are fed upon by killer whales, sharks, sea lions, and even land predators like bears and wolves. They are also huntedThey are relatively solitary animals, sometimes living completely alone and sometimes living only in small groups. The mother/pup bond is exceptionally strong due to the lack of large protective colonies. Interestingly the milk that mothers feed their pups can contain up to 45% fat.

Harbor Seals are incredibly non-vocal. While I'm sure a lot of people think of loud barking when they think of any type of seal or sea lion, the Harbor Seal doesn't bark at all. Young pups have unique cries to tie them to their mothers, but beyond that, most of the seals' vocal communication is done underwater. Above water, physical communication is far more common.

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