I've just done a page summarising Descarte's activities until the end of Episode 10, and, i wonder, would he possibly be what we could call something from the future. mods aside, you can't ride live animals, for the simple fact that they don't want to do what you want them to, and are conditioned by the game engineto be complete SOBs about it. However, Descartes could be a message from the future, information that, yes, someday we'll give you a new animal that takes you where you want to go.
Descartes, just another pig, actually does what Fart says. This could be what we're waiting for. Stay wary. Stay hopeful.