Is it easier, being green? Photo by Bas Bloemsaat.

This week at Nothing in Biology Makes Sense! I’m discussing a new study that purports to demonstrate that three-toed sloths are in a nutritional mutualism with specialized moths, fueled by algae and poop:

Sloths’ coarse, shaggy fur accumulates its own little microcosm of living passengers. (If you move that slowly in a tropical forest canopy, you’re going to get some hop-ons.) Among these are an assortment of algae, and moths in the genus Cryptoses. It’s been known for a long time that Cryptoses moths lay their eggs in sloth dung, and that their larvae eat it.

To find out why it isn’t completely crazy to think that these poop-eating moths might be helpful to sloths, go read the whole thing.◼