No, not that kind of sloth. The sloths that live in Central and South America. They're a bit of a problem for a view I develop in my forthcoming book. What I argue is is that there's a difference in life value between members of different species, based on what they can do. A chimpanzee's life has more value than a chicken's life. And that's because a chimpanzee has much richer capacities.
The ethical significance I give to capacities resonates with our experience. If you start out knowing nothing about crows, and read books about them by Bernd Heinrich, you'll find your respect increasing. You'll change your mind, gradually, about what you'd be willing to do to crows.
So, sloths. While higher capacities typically increase our esteem and respect, what's really cool about sloths is what they can't do. Listen to David Attenborough reciting their incapacities--they're nearly blind and deaf, and move very slowly. Yet this is adaptive. By doing so little, they're able to survive without very much food.
If sloths are particularly estimable, that's a puzzle for my view. I can see various things to say...but alas, the book is done. In the second edition, I will talk about sloths!