I think it was more of an adaptation at first. I'd have to get knee deep in history to work out all the details, but I know there's gotta be some story behind it.

But if you're looking for a substitute for skins, have you thought about just using fur or hair? Farmers shear sheep to make wool-- I'm sure something like that would be perfectly legal, even here.

[Even if working with a Mareep presents interesting risks, like electrocution.

Granted, all this is coming from a guy who really takes for granted his modern conveniences and sees them as a fact of life, anyway.]