Walking Ecosystem

The sloth is not so much an animal as a walking ecosystem. This tightly fitting assemblage consists of a) the sloth, b) a species of moth that lives nowhere but in the sloth’s fleece and c) a dedicated species of algae that grows in special channels in the sloth’s grooved hairs. Groom a three-toed sloth and more than a hundred moths may fly out. When the sloth grooms itself, its fingers move so slowly that the moths have no difficulty keeping ahead of them.
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