Nasty buggers, Polar Bears, and they deserve all the Algae they get.

Your Two-Toed Sloth, now, they never do anyone any harm (shut up, tree!) and they not only get Algae, they also get a fly that lives in their fur, and nowhere else.
They're never fully employed, either, and spend most of their life hanging around.

(For and on Behalf of The Seal and Sloth Federation.)