I don't know. But if it wasn't removed for some moderation issue (not saying it was, just one reason why a skin can be removed) perhaps the author is updating it. Sometimes a skin will disappear (the author can remove a skin) and then an updated version appears but that may take some time as it has to go through moderaion again.
I didn't get around to downloading that particular skin while it was up, but it looked interesting (and of course I liked the animals too).
