For thousands of years they have had to rely on catching sea mammals and fish as a means of sustenance.

数千年来，它们不得不依靠捕食海中的哺乳动物和鱼类为生。

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Humans first settled in the Arctic a mere 4,500 years ago, surviving by exploiting sea mammals and fish.

人类最早在4500年前定居在北极，靠捕捞海洋哺乳动物和鱼类生存。

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Like all sea mammals, sea leopards are curious, says photographer Bill Curtsinger. But they can also be dangerous.

摄影师比尔·克钦格说，像其他海洋哺乳动物一样，海豹非常好奇，但同时也具有危险性。

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Some birds and sea mammals affected by the spill are likely to die far offshore and never be detected, scientists say.

WSJ: Gauging Harm to Ecosystem Could Take Years

Nicotinic receptors exist in a wide range of organisms, from sea slugs to mammals.

FORBES: The Nicotine Cure

Eleven species of mammals and sea creatures, says the council, have still not recovered, including the Pacific herring, which has returned only in small numbers.

FORBES: Magazine Article