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 (magazine) owned by Active Interest Media and is based in Gaithersburg, Maryland. "EQUUS" provides information from veterinarians, equine researchers, riders, and trainers on understanding and influencing equine behavior, recognizing the warning signs of illness and disease, and solving riding and training problems. Equus (magazine) Equus is a monthly magazine for horse owners that was first published in November 1977. The intent of the magazine is succinctly stated by founding editor and publisher Ami Shinitzky's original working title: "The Horseman's Veterinary Journal". In the editorial in the first issue Shinitzky wrote, "EQUUS serves as a bridge between the veterinarian and the horse