The only dead giveaway in your picture (to me) is the head - it's not triangular. I can't see the tail, and I can't make out the back markings clearly enough (though they don't look to be diamond in shape at first glance).
It's awesome... been riding with a few other locals, went up to the lagomarsino petroglyphs this last Saturday... passed a group of 4 unimogs...they'll go anywhere just maybe not fast ;-). I'm still building up stamina... off road riding means a lot of standing on pegs, imagine 4 hours where 50% or more of your time is spent doing body weight squats.... I come back from these typically my quads are sore for several days... every time I go out I bounce back a little faster.
So far the only thing that turned me around was a 2 track trail that turned into a single track mountain bike trail winding down the side of a fairly steep hill.. If it didn't appear to keep going for 10 more miles, I might have tried to use it to get to a better road.. I was also on a 'lunch' ride so needed to get back to work at some point ;-)'
That being said, I learned to ride in the dirt.... and I think my unicycling experience helps with balance as well ;-). It works for me....