"Amazing swimmer" probably isn't the first thing that comes to mind when you think of... sloths. But they can swim about 3x faster than they can walk, and hold their breath longer than a bottlenose dolphin. Biologists think they inherited their swimming abilities from their ancestors; after all, many extinct sloths were semi-aquatic.

Nowadays, though, they probably swim to expand their reach. Moving about in the canopy is great and all, but there's lots of water in jungles, too. So, whenever a river cuts them off from food or a potential mate, they can just plop on in and paddle over. Their long arms propel them while their extra neck vertebrae help them keep their heads up. Plus, their slow digestion produces so much gas, that they basically have a built-in life vest.

So, yeah. Sloths are natural swimmers; nature is full of surprises.

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