BEaver and muskrat skins are thin. Muskrat being the thinnest. Trapped a lot of those as a teen, $5-10 a pelt.View attachment 10623
I like to imagine that the duder on the left's loincloth is made from a beaver pelt, but woodchucks and beavers are both rodents of similar size, so it'd probably work just as well to cover your junk.