It would be hard to imagine an animal more benign, more unthreatening, than a sloth. And even if they wanted to do you harm, they’d never be able to catch you.
If you aren’t able to count the claws, it’s still easy to tell the difference between the three-toed sloth and the two-toed sloth. The three-toed has a white mask around its eyes, and the two-toed doesn’t. Much easier to remember than “The pellet with the poison’s in the vessel with the pestle.”