In societies without mechanical time keeping, songs of mobilisation, calling members of a community together for a collective task, were extremely important.[1] Both hunting and the keeping of livestock tended to involve small groups or individuals, usually boys and young men, away from the centres of settlement and with long hours to pass. As a result, these activities have tended to produce long narrative songs, often sung individually, which might dwell on the themes of pastoral activity or animals, designed to pass the time in the tedium of work.[4] Hunting songs, like those of the Mbuti of the Congo, often incorporated distinctive whistles and yodels so that hunters could identify each other's locations and those of their prey.[4]