Christmas Island has bridges for crabs to stop them getting run over during the mass migration.
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Dolphins sometimes have fun by blowing bubbles and creating rings of air underwater, which they then swim through.
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Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
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Meysi is one of the world's smallest dogs, measuring in at just 7cm tall, 12cm long, and weighing a meagre 250 grams (only slightly heavier than a hamster!)
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