Human

Humans are bipedal primates that live in the Mushroom Planet and on the far away planet of Earth. Humans are one of the sapient species of the Mushroom Planet. While there are many humans in the Mushroom Planet, they are not as numerous as Toads, Goombas, Koopa Troopas, and many other species. However, humans are the dominant species of the Earth (and the only sapient species on the planet).

Humans are a remarkable and multi-talented species. They can be good jumpers (as indicated by Mario and Luigi), very strong (like Wario), very fast (like Il Piantissimo), and technologically innovative (like Professor E. Gadd). Humans evolved from early, ape-like primates and, as such, may be distant relatives to Kongs. (Toads evolved from fungus.) Apparently, Toads and humans can interbreed, as Princess Peach is part human and part Toad, since her grandmother is a Toad.

Strangely the inhabitants of Twilight Town refer to themselves as human despite their rather inhuman appearance.

Additionally, the skeletons of what appear to be humans can be found shackled in chains in several of the sunken ships in the area Gloomy Galleon in the game Donkey Kong 64.

Humans appear in the game Mario Party 8 as backdrop charecters, along with Mario enemies. They strongly resemble the Mii's of the Wii.

Origin Theories
Humans live on both Earth and the Mushroom Planet; however, no explanation has been given as to why. Perhaps, humans evolved in both worlds independently of each other. However, humans from Earth have been known to cross over to the Mushroom Planet via Warp Pipes. Perhaps early humans entered these Warp Pipes and were transported to the Mushroom Planet (or, on the other hand, perhaps early humans evolved on the Mushroom Planet and were transported to the Earth). This mystery will probably never be solved.