of riding animals are caught and tethered. A nomad's herd of horses hangs out around the family's dwelling, typically grazing several kilometres away. The herd is allowed to choose its own pasturage with little interference from the owners. They may disappear for days at a time, and eventually the owners go out to look for them. Once a horse has become familiar with carrying a rider, it will be calm, friendly, and very reliable. Because nature provides so well for Mongol horses, they cost little to nothing to raise. They are a practical necessity of everyday life, in which a substantial portion of the population still lives as nomads. Herdsmen regard their horses as both a form of wealth and a source of the daily necessities: transportation, food, and drink. The horses typically eat nothing but grass and require very little water, a trait useful for survival in environments like the Gobi desert. A horse may drink only once a day. In the winter, Mongol horses paw up the snow to eat the grass underneath. For water, they eat snow. During the winter and early spring, horses lose about 30% of their body weight. They must regain this weight during summer and fall so as to survive another year. During particularly hard winters ("zuds"), horses may starve to death en masse or die of exposure. Herdsmen can do little to save their herds in such conditions. In the bitter winter of 2009 - 2010, 188,270 Mongol horses perished. Despite their life in semi-feral conditions, most horses live to be 20 – 40 years old. The horse is believed to have been first domesticated somewhere in the Eurasian Steppe. Never have all the horses in Mongolia been domesticated at once; rather, wild and domesticated horses coexisted and interbred, so verifiably "true" wild blood no longer exists in the Mongol horses of today. However, although not considered true wild horses in the same sense as Przewalski's horse, some feral Mongolian horses browse the steppe alongside their semiferal domesticated kin. Unlike the mustangs that roam the West in the United States, which are categorized as a non-native species, feral Mongol horses are living in the same manner and place as where their ancestors had run and lived for hundreds of thousands of years. Occasionally, the nomads capture feral horses to add to their herds. History The split between Przewalski's horse and E. ferus