That's the way this Equestria works.

[Jappleack shrugs, rising up on her hind legs and leaning against a tree as she does so. It's a surprisingly fluid and human motion, and one she seems to be able to do with ease.]

I dunno. There's humans all over the place in my world, dunno why this one's decided you've all gotta be ponies too or other shit. Just one of those things, I guess.