Hinny is easier to obtain when the lower chromosome count, the donkey, is in the male. Therefore breeding for hinnies is more hit-and-miss than breeding for mules." The male hinny or mule can and will mate, but the emission is not fertile. Male hinnies and mules are usually castrated to help control their behavior by eliminating their interest in females. Female hinnies and mules are not customarily spayed, and may or may not go through estrus. Female mules have been known, on rare occasions, to produce offspring when mated to a horse or donkey, although this is extremely uncommon. Since 1527,
When a white horse is not a horse explains "'A white horse is not a horse', because the name diverges from the shape." Two "Zhuangzi" chapters (17 and 33) mock Gongsun Long, and another (2) combines his "zhi" 指 "attribute" and "ma" 馬 "horse" notions in the same context. To use an attribute to show that attributes are not attributes is not as good as using a nonattribute to show that attributes are not attributes. To use a horse to show that a horse is not a horse is not as good as using a non-horse to show that a horse is not a horse, Heaven and earth