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,
Clothed female, naked male who is nude—save for the barest wisp of fabric—while Perseus is clothed in armour. Depictions of nudity were acceptable to the 19th-century French salon culture if the setting was clearly "classical", depicting characters in a culture where nudity was commonplace, as in "Combat de coqs" (1847) by Jean-Léon Gérôme. Feminist authors Christina Hoff Sommers and Naomi Wolf have written that women's sexual liberation has led many women to a role reversal, whereby they view men as sex objects, in a manner similar to what they criticize in men's treatment of women. Clothed female, naked male Clothed female, naked male (CFNM),