how were the houynhnhnms symbol of perfection

The Yahoos represent man consumed and driven by his primal desires. The Houyhnhnms represent reason and enlightenment. The Houyhnhnms are horse-like vegetarian creatures while the Yahoos are human carnivores. They arbore violence and are emotionally and intellectually evolved. They are a species of horses that are endowed with great kindness and virtue. Gulliver lives among them for several years and afterwards is extremely reluctant to return to England