Are you sure these are natural? In their FAQ, they say:

> Is My Buffalo Vegan Friendly?

> "Yes - The shell lining we use is 100% Polyamide and our internal lining is synthetic - 100% Polyester. No animal products were used in the production of your Buffalo Systems garment.

I think that means it is synthetic, not natural. It may be possible to make fiber pile from natural fibers, but I think this company is using plastic.