Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
Equus (comics) had intended to use it against Nox, and that the King is to be executed, along with more than a dozen other members of the king's regime, Superman intervenes, feeling that the condemned men deserve a trial, again coming to blows with Equus, who carries out the execution. During the fight, Superman rips the claws right out of Equus' right arm, and seemingly defeating him. Superman then returns to Nox's palace, confronting him with the question of what he intends to do with the weapon, but Equus also appears, and ignores Nox's orders to stand down, saying that he is