Oh, that question...
So, Yoshi never goes into the shell on his back, so it must be a saddle, right? But wait... aren't there other things that don't go into ther shells?
Hmm....
Based on that theory, Clubbas have saddles on their backs as well.
Looks like Mario is in for a rough ride.
For those who don't get the irony:
I'm pretty sure it is a shell. Nintendo just loves to put shells on everything that moves. Just like they do with shoes. M&S and SSB can be disregarded as valid sources, since the former wasn't developed by Nintendo and the latter has been shown to be wrong on occasion, and to make up stuff for their own canon.
So, Yoshi never goes into the shell on his back, so it must be a saddle, right? But wait... aren't there other things that don't go into ther shells?
Hmm....
Based on that theory, Clubbas have saddles on their backs as well.
Looks like Mario is in for a rough ride.
For those who don't get the irony:
I'm pretty sure it is a shell. Nintendo just loves to put shells on everything that moves. Just like they do with shoes. M&S and SSB can be disregarded as valid sources, since the former wasn't developed by Nintendo and the latter has been shown to be wrong on occasion, and to make up stuff for their own canon.