I was reading about Mesopotamia and how agriculture altered gender relations, with women confined to the role of producing children, and men of tilling and protecting the land.  I thought that this must have been what was behind the Biblical story of the Fall.  And how people now, tried to return to the earlier paradise of providence, but by their own means.  The snake form is one that is endlessly adaptable - perhaps this is one reason it has been seen as satanic.