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,
Donkey burger to eat horse meat; however, since horses were a valuable resource, common people substituted donkey meat and considered it tastier. Donkey burgers became popular towards the end of the Qing dynasty after the Beijing-Hankou railway line was built, as donkeys were no longer needed to transport goods in and out of Beijing. When departing from Beijing, Baoding is the first major city on the Beijing-Hankou railroad. The traditional freight industry was hit particularly hard there, and as a result, donkey burgers became most popular in Baoding. Donkey burger The donkey burger () is a kind of sandwich commonly eaten in