Human

The Human species refers to the characters of Mario games that are completely homonoid, whereas most of the others seem to be of made up origin. (Ex: Bowser, Yoshis, Goombas, Bob-bombs, and the alike)

Known Humans
The following are a list of known Human characters in the games: The baby versions or other sorts of doppelgängers (Dr. Mario, etc.) of the above characters would also be humans. This is not a complete list, but it gives an idea of what characters there are in the games that are humans. Several more mentioned characters might have existed. In fact, most of these characters are in the WarioWare games.
 * Mario
 * Luigi
 * Wario
 * Waluigi
 * Princess Peach
 * Princess Daisy
 * Princess Rosalina
 * Pauline
 * Mona
 * Professor E. Gadd
 * Dr. Eggman
 * Dr. Crygor

Other humans
It is unknown whether other humans than the ones mentioned exist in the Mario realm. It would have to be concluded that there must be whole communities of other humans around somewhere, but why they are never mentioned is confusing. Are the Mario brothers, and the few other humans, outcasted from their society to live in the wild or are they of a very endangered species in a world filled with Koopas and other different enemies? It makes for a wide range of speculation of unresolved questions, though since it is a videogame, it can easily avoid this by saying it is just for the fun of the game. Anyway, there seems to be more Toads in their world than humans, which is very odd. For the next generation of humans (unless they can cross-breed with other species -- which seems to be possible, it is afterall, a videogame) it leaves very few spouses for Mario & Co. However, since mating seems to be an avoided topic (due to it being family-friendly games), this will not lead into any sort of complications. Only in the fan-fiction worlds of Mario that allow these sorts of topics will find difficulties marrying off human characters (if Original characters are not created). Especially since the male to female ratio is so high, many females would have to "service" multiple males. Perhaps this is why Bowser and DK, despite not being humans, try to capture human females, so that the human race will go extinct.