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12 animals with the longest gestation period

By: Bryan Nelson on April 28, 2010, 1:22 p.m.
A walrus pup and its mother

Photo: U.S. Geological Survey/flickr

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Walruses have the longest gestation period of all pinnipeds (a group of mammals that includes seals and sea lions), carrying their young for as long as 15 to 16 months. (Seal and sea lion mothers are also dedicated, carrying their offspring for about 330 and 350 days respectively.) Walruses also have the lowest reproductive rate of any pinniped.