Here’a a fun couple of posts from Judith Tarr:
Wow, totally an idea after my own heart! I am mostly interested in culture and sociology, but sure, let’s take a look at the biology first. Tarr looks first at a major sticking point: lack of opposable thumbs:
One obstacle might be the fact that horses are hooved animals, and therefore (humans might think) severely limited in their ability to build and manipulate technology. Even the word “manipulate” implies hands and, more specifically, opposable thumbs. Hooves in contrast are literally blunt instruments.
Elephants get around this problem by having long, supple, extremely manipulable trunks with a “finger” or two on the end. Horses don’t have anything close to this, but their upper lips are amazingly flexible and extensible. They have a surprising degree of shall we say dexterity with their teeth as well. I have one who can untie people’s shoes (and he has proved that he knows exactly where to tug, which means he has a sense of the structure of a knot; he also understands English sentences, but that’s neither here nor there, here), and there are horses who have to be locked in with combination locks or padlocks because their lips and teeth can jigger latches and fasteners.
Impressive, but I’m not too thoroughly persuaded. Still, you could tell me that a species has done more with their mouth and lips and so on than regular horses and I might buy that. Though then you might be pushing from “horse” toward “tapir.” It’s a start, though. Plus Tarr discusses other possibilities, on the grounds that ancestors of modern horses had multiple toes and there’s no reason a horselike alien couldn’t have coopted extra toes into a manipulative role.
Then she goes on into much weirder ideas . . .
Meanwhile, in the post on culture:
Herd animals may be vegetarians—mostly—but they aren’t pacifists. Their social order is built around a fluid hierarchy with the senior mare in charge, her favored seconds keeping order, and the herd stallion serving as security force, sometimes assisted by his own second who will breed the superior’s mother and daughters. Outside stallions will raid the herd and try to draw off mares, plus there’s the need to contend with predators as well as rival bands moving in on the same territory.
There is war, and it can be ferocious. Mares get into raging fights, mostly involving kicking (a horse kick is a powerful thing—just ask my dog who caught a glancing blow and now has a plate and three screws in his elbow). Stallions will wage full-on battles with battering hooves and tearing teeth…
They sure will. Lots of good stuff here. Tarr winds up:
Dang. Now I want to see how this works in a story. The psychology of a horse is not the same as that of a human, though there are some similarities. Herd structure is different from pack structure, and there’s a level of cooperation that isn’t quite so easy or straightforward for humans. Not to mention the subtlety of horse body language and the tropism toward moving in groups.
I second that! I’d love to see someone take a really serious stab at pulling this off. Elements Judith Tarr mentions that I would like to avoid in such a story: I personally have a strong distaste for Fantasy Telepathy in my science fiction, and I am sick to death of biological technology where you “grow your spaceship.” I know writers are just trying to come up with something different from human technology. But I wish everyone would try harder to avoid this total, and totally implausible, cliche.