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Seals belong to the marine mammal group known as pinnipeds. They share space on their family tree with walruses (odobenids) and sea lions (otariids). Classified as pochids in the pinniped group, true seals lack the ear flaps their sea lion cousins enjoy, and they have stubby flippers that work flawlessly in the ocean but become nearly useless on land. Their diets are varied and the amount they consume depends upon their size, which depends upon their species.
The Thing About Seals
Using their back flippers for propulsion and the front for steering, true seals appear to fly as gracefully as any bird when traveling through water. On land, they flop along on their stomachs in bumbling gaits that make them easy catches for their land-based predators, mainly humans and polar bears. Sea lions, walruses and other members of the pinniped family can use their larger and stronger flippers to “walk” on land. True seals will never climb aboard a pedestal at a show or toss a ball to entertain you. Such roles are reserved mainly for the sea lions and walruses of the pinniped clan.
Achieving Pleasingly Plump Status
Baby seals begin life with voracious appetites. They need to gain as much weight as possible, as quickly as possible. Most species' mothers nurse their pups for just a few weeks before abandoning them on the shore. Female northern elephant seals attend to their pups for 28 days. Born weighing approximately 75 pounds, Northern elephant seal pups pack on approximately 10 pounds a day, nearly 300 pounds, before mom returns to sea. The pups fend for themselves for another two months, practicing their swimming and developing hunting skills on squid and small fish before departing for open waters, where they’ll live until mating season begins again in the spring.
Quantity Vs. Quality
In general, seals consume 4 percent to 6 percent of their body weight daily. The average male grey seal, sporting a dark gray coat with silvery spots, weighs approximately 880 pounds and requires 35 to 52 pounds of food daily. His diet consists of fish, crustaceans, squid and octopuses. The National Oceanic and Atmospheric Fisheries Office of Protected Resources notes gray seals also snatch seabirds for a snack when given the opportunity. The relatively diminutive harbor seal weighs 300 pounds on average and needs only 12 to 18 pounds of seafood on his menu daily. The gargantuan male northern elephant seal maintains a body weight of approximately 4,500 pounds and must consume 180 to 270 pounds of food every day.
Feasting and Fasting
Since female seals fast while their pups are nursing, both mom and baby benefit from the blubber the mother seal stores during her 11-month pregnancy. Weaned pups lose pounds once mom leaves them on shore, sometimes as much as a third of their body weight. Dehydration and starvation are significant risks among weaned seal pups. The Marine Mammal Center, which provides rescue and medical attention for sick seals in California, notes underweight elephant seal pups are common patients from February through June, some weighing only 100 pounds.
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