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,
What A Summer What A Summer What A Summer (foal in 1973) was an American Thoroughbred Champion racehorse who defeated both male and female competitors. She was bred in Maryland by Milton Polinger. She was a gray out of the mare Summer Classic who was sired by Summer Tan. Her sire was What Luck, a multiple stakes winning son of U.S. Racing Hall of Fame inductee Bold Ruler. What A Summer is probably best remembered for her win in the Grade II $65,000 Black-Eyed Susan Stakes over stakes winners Dearly Precious and Artfully on May 14, 1976. What A Summer was trained very