If you’re building a world with horses in it, you’re creating a particular kind of environment. If you change that, or miss any of the essentials, you’ll have to either do more homework or think about genetically engineering your equinoids.
Horses can range rather widely in size from medium-small dog (see above re. genetic engineering; also, bear in mind the nature and ramifications of dwarfism) to small elephant (genetic engineering again, and gigantism). Optimally however, you’re looking at an animal weighing around half a ton and standing around five feet at the shoulder.
Size down for very harsh climates and low-quality forage–say, Iceland, or the Shetland Isles. Size up with care; very large horses are very inefficient in terms of fuel and stamina, and have difficulty maintaining soundness. Mostly, very big horses are conversation pieces; they may be used as draft animals or for pulling large vehicles, but for riding are rather in the category of the semi-trailer or the monster truck.
Whatever their size, horses need plentiful grass-type forage. They evolved as steppe animals (with a subset of desert runners); the first humans to domesticate them were probably nomads, and in the beginning horses were probably hunted for meat, then domesticated for meat and milk. Driving and riding came later.
Basic infrastructure for horses, therefore, requires a lot of land and a lot of forage. Even horses kept in cities and used as transport will still need breeding farms with acreage, because young horses must have ample exercise (and space to do it in) in order to develop properly. Grow a horse in a box (some barely larger than the horse’s own body; others large enough for him to turn around but not to walk or run in–say, eight or ten feet on a side) and you get an animal without the strength or stamina to be ridden or driven.
One solution to this problem in cities is to keep the mare in work right up until she foals, then as soon as the foal is on its feet, start taking baby to work with mom. Baby learns to follow and keep up, and as it grows, the drover or cabman will start tying the youngster to the back of the vehicle, then by the time it’s a year or two old, put it in harness and put it to work alongside its mother.
This is not necessarily humane, but subsistence-level societies for the most part can’t afford to be. Animals exist for the use of the human, and the human makes maximal use of them, even at the cost of shortened lifespan and decreased health and soundness.
Urban horses still have to eat grass in some form–cut and dried as hay, processed as pellets, eked out by feeding straw to provide roughage while grain provides concentrated nutrients. An all-grain diet is a horse-killer; it’s too rich. But a diet of low-nutrition grass or straw, supplemented by concentrates, will keep a horse alive and even thriving where large pastures and open fields are not an option.
Your world still needs agricultural lands, notably hayfields, but those can be a considerable distance away from the city. Then you have to build a transportation system that is both efficient and reliable, for getting the hay and grain to the horses, along with tools for processing the feed, and vehicles for transporting it, and classes of workers to grow and harvest the product and man the transports.
In the city, meanwhile, the horses have their entourages. People with money to provide stabling, buy feed, and equip the horses. Stablehands to care for them, horse doctors to treat injuries and ailments, blacksmiths and farriers to provide everything from shoes to the metal fittings for harness, trainers to teach both horses and handlers what they need to know. There will be dealers in hay and feed, makers and purveyors of equipment (from ropes and halters to saddles to harness to wagons and coaches), and builders of stables and enclosures. There’s a whole economy that revolves around the horses.
It’s true even now. Do a web search on “horse tack” and see how many thousands of links turn up. Horses are big business, and would have been considerably more so when they were the main mode of transport.
Don’t forget water sources, either. Horses need a lot of hydration, especially if they’re working hard in warm climates. A city under siege would have to consider rations for the horses as well as the humans–and might opt to eat the horses rather than funnel off scarce resources to keep them fed and watered. The consideration there would be whether and how much the horses were needed as transport or as vehicles for war (battle chargers or chariot teams), and whether the loss of them would put the defenders at a disadvantage.
One solution would be, early in the siege, to send the horses away under guard to some hopefully safe area with plentiful grazing and water. Another would be to break the siege early with an all-or-nothing charge, and hope to drive the besiegers off. Either gamble could fail, of course, but such failures make good stories.
Outside of war, horses can do a great deal to foster communications within a preindustrial empire. Networks of posthouses and couriers’ stations and caravanserais can connect towns and cities and even nations, and expand trade and speed up the passage of information across wide stretches of landscape. In a landlocked country, where navigable rivers are few and oceans nonexistent, the speed and maneuverability of the horse makes larger empires possible. He can, with care and planning (and a long, unbroken supply line), cross deserts and scale mountains, and then hold them all together with rapid communications.
Don’t forget roads, either. Modern asphalt and hard surfacing is designed for the rubber tire; railroads run on metal rails. Horses need a softer surface, preferably as close to that of a grassy field as possible. Dirt roads (which turn to mud when wet, and to dust when dry) are pretty much essential. Paving of some sort has to have texture to keep hooves from sliding and causing falls; it can’t be too hard or hooves wear down and the horses go lame. Horses may be shod to help with this, but metal shoes wear down, too, and need constant repair and replacement.
I think it may be harder in our culture to build a world without horses or horselike animals than to build one with them. An empire built on foot would have a different measure of speed, a different system of transport–all based on how fast a human can run or swim, and how much weight he can pull or carry–and a different theory and praxis of road construction. The wheel might not happen, or be confined to the potter’s wheel or the spinning wheel; then technology will develop in different directions, with different emphases and basic assumptions.
It’s amazing really how much the culture and mythos of the horse has influenced the development of modern Western society–from the structure of its cities to the way it designs its no longer horse-drawn vehicles. We even still measure our engines in “horsepower,” though it’s been well over a century since horses dominated our transportation system. If we’re building a world without these elements, we have to rethink many of our basic assumptions, and come up with a different way for the world to work.
For more precise details about the subjects mentioned in this blog, check out Writing Horses: The Fine Art of Getting It Right. Questions answered, terms defined, and links, many links, to further investigations. With copious illustrations. Just $4.99 in all the popular formats (including Kindle, Nook, and Sony e-reader) from the Book View Cafe e-bookstore.
Or if you’d like to see one way in which horses can be portrayed in fiction, try A Wind in Cairo, the magical story of a prince, a Turk, and an Arabian stallion. And for further historical delights, try The Dagger and the Cross: A Novel of the Crusades and its prequel, Alamut.