Not only is that not a rub, I would venture a guess that that is not a deer bed, but rather a bear's day bed. I have never seen a deer bed with the ground cover scraped away like that.

As mentioned by GMMAT, deer do not generally bed in the exact same bed repetedly. Bears on the other hand frequently will scrape an area clean (often at the base of a large tree, like in the picture) and use the same bed for days or sometimes weeks.

I suspect that your "buck" has black fur. -Sharps