A three-toed sloth (Bradypus variegatus) makes its slow and ungainly maneuver across a dirt road before ascending back up to the canopy. Like this individual, male three-toed sloths are characterized by a distinct light orange dorsal patch of hair with a black stripe. Sloth hair is thick and coarse to the touch and acts as an entire ecosystem with almost 1,000 invertebrates found on a single sloth along with symbiotic fungi and algae. Notice the sloth moths (Pyralidae: Chrysauginae) in some of the photos and video. Over a year ago I helped a sloth off the road and a few of them were transferred onto me (one escaped from my shirt hours later), so maybe I have my own walking ecosystem now too. These moths live in sloth fur during their adult stage, and females deposit eggs into sloth feces when sloths descend to defecate on the forest floor. The larvae are coprophagous, and once pupated they fly to the canopy in search of a host sloth. Decomposing sloth moths may help fungi thrive, which in turn provide nutrients for the algae, ultimately taking part in a sloth’s diet.
Photographed in situ [1]
Last year I helped a sloth off the road in Costa Rica. Below is video footage of that encounter:
So, why does the algae grow on the sloth just to get eaten?