The immediate ancestor of Bos taurus, the common dairy cow, was Bos primigenius, the long-horned wild aurochs. This massive animal, standing 6 ft/180 cm at the shoulder and with horns 6.5 in/17 cm in diameter, roamed Asia, Europe, and North Africa in the form of two overlapping
races: a humpless European-African form, and a humped central Asian form, the zebu. The European race was domesticated in the Middle East around 8000 BCE, the heat- and parasite-tolerant zebu in southcentral Asia around the same time, and an African variant of the European race in the Sahara, probably somewhat later.