 Some people put bells on their livestock because they believe the foreign sound of the bell scares off predators, however, some studies have shown that the sound of the bell has the opposite effect and leads predators to livestock because predators develop a learned association between the sound of the bell and the presence of a prey animal.It is difficult to pinpoint when exactly the use of cow bells began, but the earliest examples of truly recognizable cow bells date back to the Iron Age.The use of iron bells in sub-Saharan African music and the Niger–Congo area is linked to the early iron-making technology spread during the Bantu migrations.