John Calvin Commentary Genesis 36:24

"And these are the children of Zibeon: Aiah and Anah; this is Anah who found the hot springs in the wilderness, as he fed the asses of Zibeon his father." — Genesis 36:24 (ASV)

This was that Anah that found the mules. Mules are the adulterous offspring of the horse and the ass. Moses says that Anah was the originator of this crossbreeding.

But I do not consider this to be said in praise of his ingenuity, for the Lord did not distinguish the different kinds of animals from the beginning without purpose. Indeed, since worldly vanity often tempts people, causing them to focus on unnecessary things, Moses highlights this unnatural pursuit in Anah. Anah did not consider it enough to have many animals; instead, he had to add to them a debased breed produced by unnatural breeding.

Moreover, from this we learn that there is more moderation among mere animals in following the law of nature than there is in humans, who invent corrupt mixtures.