Without reference? That's pretty good

As for crits, I have just a couple; I think the individual parts are generally pretty well done,
but the way they're put together w/ the rest of the fox is a little rocky in places. For example,
the ear (near side) - the part that connects to the head on the inner side should probably be
more up & back. The whole base of the ear ought to flow w/ the skull & blend smoothly w/ the
topline. The forehead should also have a -slightly- more gradual slope to it, instead of being
rounded, then suddenly having the muzzle jut out. You might also want to give him a little bit
more of a bottom jaw - it's not terribly off, but seems to be a tad too thin in the middle.
But other than that, I think you're off to a very good start w/ realism :3 Some things I like
in particular are the eye, nose, lip and chest-fluff. You've also got the general idea of which
way the fur flows; you might want to take the next step w/ that and try to define the individual
layers, instead of the general gist of it.
*tailwag* Hope you continue w/ the realism, looks like once you get a few of the more subtle
details down, you'll be great

Here's a few good references I found that could help...
http://animals.nationalgeographic.com/s ... eeping.jpghttp://www.pgc.state.pa.us/pgc/lib/pgc/ ... ed_fox.jpghttp://www.julietchapman.com/Workshops/ ... 20snow.jpg