Blue whales are the largest animals ever known to have lived on Earth. These magnificent marine mammals rule the oceans at up to 100 feet long and upwards of 200 tons. Blue whales reach these mind- boggling dimensions on a diet composed nearly exclusively of tiny shrimplike animals called krill. Blue whales are Baleen Whales, which means they have fringed plates of fingernail-like material, called baleen.

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Blue whale