The whole 'alpha' and 'sigma' labels feel more like a convenient shorthand for certain character archetypes than a rigid biological rulebook, at least in how I see them used across genre fiction. In a traditional pack structure, like you'd find in a classic werewolf or shifter romance, the established order has the alpha at the top. It's a leadership role, often tied to strength, charisma, and responsibility for the whole group. The sigma, by contrast, is defined by operating outside that hierarchy, a lone wolf by nature.
So, can a sigma be 'higher'? Not in the official chain of command, no. But 'dominance' gets murky. I've read books where the true power lies with the sigma outsider precisely because they don't play by the pack's rules. The alpha might command obedience through position, but the sigma commands attention—and sometimes fear or respect—through unpredictable actions, deep-seated power others don't understand, or a chilling indifference to the social order everyone else is scrambling within. Their influence isn't positional; it's gravitational. They pull the plot's strings without needing a title.
In a story context, that often makes them more narratively dominant, even if the alpha is technically in charge. A classic example is the mysterious mentor or the ancient being who doesn't bow to the pack alpha but whose knowledge or raw power makes them the ultimate authority in a crisis. The tension between the alpha's societal dominance and the sigma's intrinsic dominance is what drives a lot of those stories.