Researchers compared congenitally blind athletes to seeing athletes and found both groups “puff up” or open themselves up when they win (outstretched arms and shoulders, big smile facing up and out), and cower and close inward when they lose, implying the behavior is an innate tendency of humans.
This study made me really curious about my husband's "bellowing," which he is actually known for internationally: when he accomplishes a large physical feat like scaling a wall or landing a jump, he cries a mighty bass-toned yawp... okay, it's more of a war bellow, like he has defeated an elk in hand to hoof combat. But this study has made me wonder if his mighty yawp is the same primal instinct as the "warrior pose." Jumping up and down and squealing, "I win, I win" isn't going to scare away many other predators or challengers: roaring like a grizzly bear on the other hand and making yourself big is going to make a lot of critters think twice about coming after you, including the grizzly bear.
This also leads me to wonder if dominant males (of any primate species) celebrate their victories more often or louder than less dominant males. Obviously behavior is going to be curtailed by social expectations (Japanese and Scottish Highland cultures very much discourage individualism and show-offiness, for example), but it seems plausible that a dominant male would (a) win hand to hoof combats more often and so have more opportunity for bellowing, and (b) be more vocal and more physical in his reaction to that victory. This in turn would intimidate a lot of non-dominant folks and would discourage any challengers. *feminist note*: I'm wondering mostly about dominant males and their victor display because females don't typically puff up or roar to show their dominance over others. They will yell, and are violent, but at least the wolf, chimp, and human studies I've seen point to quicker, more subtle expressions of dominance from females.