Mules

A mule happens when you breed a donkey and a horse. They do not occur naturally in Minecraft. Once they are tamed youcan mount a saddle on them to direct them and you can also mount a chest on them to give them 15 extra carrying slots which makes them useful for transporting materials to a new house or taking large quantities of ores and stones from a mine.

link back to mob info page.

Link to How to tame horses, mules and donkeys.