that makes all of the furry porn that you've seen considerably more colorful, does it not?
edit super props go to starspiritgate for an online source: http://www.jbc.org/cgi/reprint/93/2/805.pdf
"Through the kind cooperation of Mr. Champion Holland of Albany, Prince Edward Island, and Mr. G. Ennis Smith, Superintendent of the Experimental Fox Ranch at Summerside, Prince Edward Island, several samples of fox milk, preserved with thymol, were sent to our laboratory. The composition of these samples is given below in so far as the amounts permitted of analysis. The milk can only be obtained in the spring and from an animal that is relatively tame.
The first sample was taken at a single milking on May 8, from a healthy, well furred, medium silver fox that had given birth to four puppies on April 11. In appearance it was of a slightly yellowish color, of a thick, creamy consistency, and of a faint, asphalt-like odor."