Transhumance is a "form of pastoralism or nomadism". The origin of steppe pastoral nomadism is poorly understood. The music of Mongolia is strongly influenced by nature, nomadism, shamanism, and also Tibetan Buddhism. The origin of steppe pastoral nomadism is not well understood. Some males, called 'floaters', switch between territoriality and nomadism depending on availability of females. The origins of pastoral nomadism and horse archery are not clearly understood. The prefabricated felt yurt satisfies the conditions of Mongolian nomadism. There is practically no economical infrastructure and the main activity is camel herding nomadism. These tribes lived in tents and practiced nomadism. The western Sudan had a mixture of peasant agriculture and nomadism. He was also a scholar of popular culture, archaeology, nomadism, and botany. Eastern Sudan had primarily nomadism, with a few areas of irrigation and agriculture. By the end of the eighteenth century, Mongolian nomadism had significantly decayed. They are not migratory, but show nomadism in response to weather and food availability. Where grass is poor herds must be moved, which leads to nomadism.