Sorry ray. I found this: Experience demands that man is the only animal which devours his own kind, for I can apply no milder term to the general prey of the rich on the poor.
http://www.brainyquote.com/quotes/authors/t/thomas_jefferson.html
So if it's not a quote by Jefferson, it is an honest mistake.
I like this one: If a nation expects to be ignorant and free, in a state of civilization, it expects what never was and never will be. (ibid)