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,
Africanus Horton Africanus Horton Africanus Horton (1835–1883), also known as James Beale, was a Krio African nationalist writer and an esteemed medical surgeon in the British Army from Freetown, Sierra Leone. Africanus Horton was a surgeon, scientist, soldier, and a political thinker who worked toward African independence a century before it occurred. In his varied career, he served as a physician, an officer in the British Army, a banker, and a mining entrepreneur. In addition, he wrote a number of books and essays, the most widely remembered of which is his 1868 "Vindication of the African Race", an answer to the white