In the past, this order contained 14 families, but only three—Equidae (the horse and related species), Tapiridae (the tapir), and Rhinocerotidae (the rhinoceroses)—have survived to the present day.
No pasado, está orde contiña 14 familias, pero só tres delas —Equidae (os cabalos e especies relacionadas), o tapir, e o rinoceronte— sobreviviron ata a actualidade.