Most Mutants and Masterminds characters can be said to be “superhuman”, but some were never human to begin with. It’s a great big universe, and Earth is by no means the only populated planet, so you’re character could be an Alien. And this great big universe of ours is only one part of The Multiverse, so there are some character options there.
Whether extra-terrestrial, extra-dimensional, or something else, some characters have Powers that are normal traits for members of their species. In game terms, this is handled by giving Power Effects the Innate Extra (see page 142 of the rulebook).
The sky is the limit for players wishing to play a non-human character, but here some examples of other species that exist in this campaign. Some of these pages also have some game rule information, usually showing “Species Traits” Powers to establish consistancy with characters of that type.