How is Centaur not a species option?

A color mock-up for a centaur character I wanted to make! The lineart was designed by me but drawn by the amazing kherrigan. I love piebalds and zorses have big white areas on their bodies, so I thought a 'piebald' zorse would look super cool. I think I was right. Not sure if I will keep this design, but it's my favorite so far

Carl is not his name, Carl is an inside joke between friends that has just become the name I use to refer to him until I give him a name. I want to give him a Dothraki name because I'm a huge nerd. Right now I'm thinking Hrazo (he who is like a horse) or Jorro (he who is an idol, sort of like he's an idol of Vezhof, the Great Stallion, god of the Dothraki). Karlinno (he who gallops) is another option because then I can keep calling him Carl. >_>

PS He's not old, the white hairs are from his piebald gene...I guess