Our friend Zach sent us this great cam picture a few years ago of two does squaring off. Notice how the other girls are standing around and staring, urging them on. A deer fight is pretty much like a people fight!
Why do does do this? Texas Parks & Wildlife says it better than I could on their page about whitetail body language:
Female deer also establish a peck order and display aggressive behavior. Does, like bucks, use the ear drop, hard look, and sidle body language. However, since they don’t have antlers, they use their front feet to determine their dominance. If the preliminary body-language threats are not effective, the dominant doe lunges at her adversary and then strikes out with one or both front fee. As a last resort, the fighting does stand up on their hind legs and slash out at each other with both front feet. Their sharp hooves are wicked weapons, and the does do not bluff or fight mock battles.