No, not really a smile but it kind of looks like it. The deer rut is pretty much over but there are still some lingering signs of it. I am still occasionally seeing some bucks sparring and in this case, see them sniffing the ladies.
This handsome brute is displaying the flehmen response, a curling of the lips and opening of the mouth that allows it to get a nice, big whiff of scents. It is much like you or I take a big whiff with our nose.