A false arm of the Great Rift Valley runs southeast from the Ngorongoro Highlands to Lake Eyasi, a shallow alkaline lake that can vary in size considerably from one year to the next. The Datoga people graze their livestock on the friable, volcanic pasture land around the lakeshores.The Datoga (known to their Maasai neighbours as the Mang'ati and to the Iraqw as Babaraig) live in northern Tanzania and are primarily pastoralists.