Zebra black and white at birth. Plains and mountain zebra foals are protected by their mothers, as well as the head stallion and the other mares in their group. Grévy's zebra foals have only their mother as a regular protector, since, as noted above, Grévy's zebra groups often disband after a few months. Attempts have been made to train zebras for riding, since they have better resistance than horses to African diseases. While occasionally successful, most of these attempts failed due to the zebra's more unpredictable nature and tendency to panic under stress. For this reason, zebra-mules or zebroids (crosses between
Zebra of southern and eastern Africa. It, or particular subspecies of it, have also been known as the common zebra, the dauw, Burchell's zebra (actually the subspecies "Equus quagga burchellii"), Chapman's zebra, Wahlberg's zebra, Selous' zebra, Grant's zebra, Boehm's zebra and the quagga (another extinct subspecies, "Equus quagga quagga"). The mountain zebra ("Equus zebra") of southwest Africa tends to have a sleek coat with a white belly and narrower stripes than the plains zebra. It has two subspecies and is classified as vulnerable. Grévy's zebra ("Equus grevyi") is the largest type, with a long, narrow head, making it appear rather mule-like.