Not much is known about donkeys yet.
Donkeys are found in hill areas or plains. They can be tamed with a golden apple, but only if a saddle (not a horse saddle) is present in your inventory. When tamed you can give it a chest so it has its own inventory. On death, they drop 2 leather and one or two steaks. It takes 9 hits with a wooden sword to kill. There are four colors of donkeys; white, grey, light brown and (reddish) dark brown. Unlike Yogbox horses, donkeys are able to climb blocks on their own without the need to press the jump button. They are able to climb over fences, but normally do not roam much.