Wasn't there an article on the old CYD website that showed the existence of a brothel in the 1890's to 1900's that catered to customers who wished to pretend to be animals fucking other animals? They all wore fursuits, too. Very elaborate ones made of real fur at that. They had stories of the prostitutes dressed as rabbits (remember: Full fursuit type, not the Playboy bunny), while some of their clients dressed up as wolves, and they went at it in some makeshift meadow in the place.
The whole existences of furries in the modern world should not have come to any surprise to anyone. I daresay that if you went back in time and made computers with internet access available to the masses in the 1880's, there is no question in my mind that just as many fetishes, furries included, would have shown up. Technology and a more tolerant society is all what is needed for any group to exist.