Seasonal movement of pastoral groups over long distances, between higher and lower altitudes, or other climatic zones, for the grazing of livestock. Masses of livestock are herded to pastures at high altitudes or in colder regions in the summer, and brought back for the winter when the former are uninhabitable. Often entire communities migrate, establishing temporary settlements along the route; however, they typically have one permanent settlement and also engage in agriculture. The practice draws on ecological knowledge developed and transmitted over generations, and is closely linked with various sociocultural and economic activities including specific handicrafts, food cultures and seasonal festivals. Derived via the French from the Latin trans- ‘across’, humus ‘ground’.