[QUOTE=Lightray]
Really, the answer seems to be that we do not have riding zebras, not because it couldn’t be done, but because no one had the need to do it. I’m not up on the cultures that developed in zebra-country, but I suspect their lifestyles would not have benefited from zebra-chariots, zebra-carts, riding-zebras, zebradrawn-plows, or other zebra-related innovations.
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See, I don’t agree with this. Those sub-saharan african kingdoms really could have used zebras as domestic animals, except they just never tried to domesticate them. And when they saw examples of horses being used to good effect by outsiders, they didn’t imagine domesticating their native similar species, instead they figured they needed to get some of those horses for themselves.
Or take, I don’t know, ostriches. Ostrich ranching is (or was) all the rage. Ostrich ranching isn’t impossible, so why didn’t sub-saharan africans practice ostrich ranching? Sure, ostriches are dangerous, but are they more dangerous than a bull or a ram?
Now, about those moose. (Alces alces, what we call moose in American english is usually called “elk” over in Europe, while what we call “elk” (Cevus elephas/canadensis) is called “red deer” over there. So while those Swedes never domesticated moose, Rangifer tarundus was domesticated in northern Eurasia. Except in the Americas, the exact same species is present except it was never domesticated.
If we believe that just about every animal that could be domesticated WAS domesticated, why is it that caribou were domesticated in Eurasia but not America?
And my answer is that reindeer were probably domesticated in Eurasia only after a long history of pastoralism. And then on the northern limits of goat and sheep and cow and horse animal husbandry, herders started with reindeer. And the difference is that reindeer really can fill a function completely different than a cow or a sheep or a goat, because they can thrive in regions that are too cold for the standard eurasian suite of domestic animals. But without that pre-existing herding culture, the idea to attempt to domesticate reindeer never would have happened. And the domestication project was only successful because reindeer herding was possible in places where other herding was impossible, the reindeer wasn’t just a half-assed sheep or goat, it was something else entirely.
But in the Americas there was no such tradition of pastoralism. And so no Innuit hunter is going to get the idea to give up herding sheep and take up herding caribou, because he had no sheep in the first place. And it wasn’t until the 19th century that the attempt was made to introduce eurasian style reindeer herding to Alaska. Unless your society is already a herding society, the likelihood that you will incorporate new domestic animals to herd is pretty much zero. Except not exactly zero, because we have those sheep, goats, cows, pigs, horses, and chickens to account for.
So my theory is that a domestic animal requires a niche in human society to exist. And existing domestic animals fill most existing niches, so any potential new animal must fill a niche that isn’t filled by any other domestic animal. And not all human societies have the same niches available. Hunter-gatherers only have dogs. Herders and farmers have plenty of space for domestic animals, but those spaces are already filled. And modern society has unlimited space for just about any crazy domestication program, because we can do it for fun, or as a multilevel marketing scam, or so on.