[Uros Osium Tokker]

There are humans on Mudos? Well not in Mudos really :3 Mudos I left in cannon with the basic story of Abe, Munch and Stranger as I used the land across the sea which I named Escoria.
However as to why there are humans in Oddworld? Well, as explained before I used one of the theories about evolution which explains that DNA come from space (Probably in comets and meteors) but since the ecosystem in Oddworld is different (Planet size, probably temperatures, etc... not including wildlife and such) the DNA didn’t properly work it out to survive on its own.
So why we can find these guys in Escoria? When the Glukkons came to conquer the place with security and Vykkers they found the DNA to be so simple in comparison with most the creatures in Oddworld that they could manage to clone the human kin.
Explanation: Humans are highly adaptable beings but our bodies are a bit crappy you know? The only thing that has evolved to be semi supreme is the brain while bodies and anything related has regressed more than evolved since we need of the technology for everything (from weapons to immunity to our system and other things). Most creatures in Oddworld are so special and so attuned with their elements and environment that it is near impossible to reproduce it easily… Human simply leech of anything they can get their hands on it instead of trying to flow with it (This is in general for the species). Since our kin is not so well made, doesn’t have a queen (at least like they have in Oddworld) and simply are even more Industrial than the Glukkons… well the technology can easily reproduce them :3.
Lets face it: A Paramite is more evolved than us, probably. A Mudokon or a Glukkon is simply eons away from us.
In resume: There are humans cause of dumb luck (some DNA landed on the continent of Escoria and was found), the greed for easy profit the Glukkons have as well as the hopes for new toys the Vykkers can use for experimentation >:3
This is possible? Probably. Cannon? Nope :3 But I thought it was worth a shot and here it is ^^.