The game has an extensive character creator for humans and pets alike, which allows you to choose from a wide variety of horse breeds or mix, match and edit every detail yourself. In the case of The Sims 3 and its Pets expansion, your sims can become jockeys and horse breeders.
In countless iterations and expansion packs, what those lives can look like has been reinvented over and over.
The Sims franchise is all about simulating and playing out the lives of individual fictional people.