Narwhals can be called whales of the ice: in icy channels, ponds, and ice-shielded bays they seek sanctuary from killer whales, their chief predator, and their annual migrations following the seasonal rhythm of advancing and retreating ice.
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Atheir annual migrations following
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Btheir annual migrations which follow
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Ctheir annual migrations follow
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Dwhose annual migrations following
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Ewhose annual migrations follow
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