Those hybrids are called "Cebroide" in my native tongue. I'm not found on mixing species like this, but donkeys and zebras are pretty closer. Such mix makes me remember wild african ass.
Nice photo, I'm not used to see them
They've crossed Zebras with Shetland Ponies as well as other full-sized horses. I have two pictures I've scanned out of horse magazines. I think it's way cool, yet way weird. If zebras are stubborn, and you cross it with a donkey...you get one REALLY stubborn animal!
Awesome shot though. Poor thing needs a better fitting saddle and it's belly strap is too tight, but whaddya do? He's all cute & fuzzy.