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,
Phrynobatrachus africanus Throat is dark grey in males but spotted with brown in females. "Phrynobatrachus africanus" occurs in lowland swampy forests. It can survive in somewhat degraded forests, but not in open habitats outside forest. Males call from cavities and holes near streams. Breeding takes place in pools with standing water along streams. It is a very common species. It can be negatively affected by loss of its forest habitat caused by logging, agricultural encroachment, and human settlements. It occurs in several protected areas. Phrynobatrachus africanus Phrynobatrachus africanus (common name: African swamp frog) is a species of frog in the family Phrynobatrachidae.