The Furry Ecosystem of Algae, Moths and Sloth Feces

Humans generally don’t like it when things grow on them, whether it’s a bacterial infection, a cancerous tumor, or, for parents, the latest Cocomelon song. But it’s a different story for our mammalian relative the sloth; not only do sloths not mind things growing on them, they actively encourage it in one of the most striking mutualisms known to biology.