Giant Sloths Were Hairy

Paleoart by Syed Jaffri.

A recent study has found that giant sloths (megatheres specifically) had a metabolism similar to that of modern xenarthrans, thus making an argument that, unlike modern “pachyderms”, giant sloths more likely retained their lengthy hair.

This comes at the tail end of a wave of skepticism on the part of paleontologists on whereas large tetrapods retained hair/feathers at giant sizes. A key voice in this discussion has been Mark Witton, which has argued dinosaurs above a ton were most likely featherless and has in fact depicted giant sloths as hairless.

This study is the first “formal” disagreement with this line of thinking, and suggests that factors in regards to extinct animal integuments were complex and multifaceted. Notably, dinosaurs smaller than a ton like Psittacosaurus were featherless and others just above it like Yutyrannus had feathers (although admitely it lived in a cool environment), and elephants (which have lower body temperatures than most mammals) are largely hairless.

Examining these sympathies of environment and metabolism is the first step to understanding the life appearence of these wonderous animals, though of course nothing replaces actual integument.

Now excuse me while I design giant fluffy gondwanatheres.