This is not the story of how the sloths came to be.
That story is old, and dangerous, and far too long to tell on poles. For the sloths have been in Ur far longer than most suppose. Before the first butterfly flapped it's wings, before the first chicken warmed an egg, the sloths hid in the trees and quietly watched the world pass them by.
They did not go entirely unnoticed. Legends passed from glitch to glitch of strange creatures hidden up in the dry rocks of the north-eastern heights. It was said that if you mined the right kind of rock next to the right kind of tree, if you were very lucky you might hear a soft voice singing of copper and tin. These legends eventually came to ear of the Giant Zille.
Now normally Zille has no interest in animals, leaving them to her sister-Giant Humbaba. But these animals sang of stone and metal, not of meat and grain, and Zille was determined to hunt them out. Perhaps she had dreamed them herself, and then forgotten about it.
After much searching, Zille found the sloths and heard their song. She found it beautiful, and told the sloths, and they were glad. But they would not share their song with the glitches of Ur, because they were shy.
"What if the glitches loved metal too?" said Zille. "From your trees you can only watch them mine. If you spoke to them they could give you metal, and you could share your song in return." The sloths had not thought of this, and decided to give it a try.
And so Zille found an acolyte who loved metal with all their heart, and asked them to share their metal with the sloths. The sloths took the metal, and chewed it, and sang, and the acolyte was overjoyed to find themselves inundated with little metal snails, just the perfect size for building and crafting.
And so the sloths came out of hiding, and their songs of metal rang across the hills of Ur.