Why haven deer been domesticated (like horses for riding, etc.)?
It might be possible to ride a moose (elk), or an elk (wapiti, or red deer) and some of the other larger deer.. The trouble with riding deer is those antlers, after riding a deer for a day you are sore on both ends. The Lapps of Finland have domesticated the reindeer for centuries. The situation is less like the horse than the cow and oxen, and is nomadic herding rather than farming. The Lapps use them for food, hides, even milk, and for pulling sleds. Children and older people do ride them as they travel from grazing ground to grazing ground. The Lapps also saw back the antlers when they harden, (BTW unlike other deer both the male and the female reindeer and the caribou(its wild American version) have antlers. The reason deer aren’t more widely domesticated probably has more to do with the nature of the beast, they usually don’t readily take to close contact with human domesticity. Even on those ‘farms’ they are basically living fenced in but in a more wild condition than most cattle