festivals. These social strata, like caste systems found in many parts of West Africa, included singers, musicians and story tellers of the Tuareg, who kept their oral traditions. They are called Agguta by Tuareg, have been called upon to sing during ceremonies such as weddings or funerals. The origins of the artisanal castes are unclear. One theory posits a Jewish derivation, a proposal that Prasse calls "a much vexed question". Their association with fire, iron and precious metals and their reputation for being cunning tradesman has led others to treat them with a mix of admiration and distrust. According to Rasmussen, the Tuareg castes are not only hierarchical, as each caste differs in mutual perception, food and eating behaviors. On this point, she relates an explanation by a smith on why there is endogamy among castes among Tuareg in Niger. The smith explained, "Nobles are like rice, Smiths are like millet, Slaves are like corn." In the Tuareg areas of Algeria, a distinct tenant-peasant strata lives around oases known as izeggaren (or haratin in Arabic). Traditionally, these local peasants were subservient to the warrior nobles who owned the oasis and the land. The peasants tilled these fields, whose output they gave to the nobles after keeping a fifth part of the produce. Their Tuareg patrons were usually responsible for supplying agricultural tools, seed and clothing. The peasants' origins are also unclear. One theory postulates that they are descendants of ancient people who lived in the Sahara before they were dominated by invading groups. Some speak a Songhay dialect along with Tuareg and Arabic. In contemporary times, these peasant strata have blended in with freed black slaves and farm arable lands together. According to the historian Starratt, the Tuareg evolved a system of slavery that was highly differentiated. They established strata among their slaves, which determined rules as to the slave's expected behavior, marriageability, inheritance rights if any, and occupation. The Ikelan later became a bonded caste within Tuareg society. According to Heath, the Bella in the Tuareg society were the slave caste whose occupation was rearing and herding livestock such as sheep and goats. West Africa Fula people The Fula people are one of the largest and a widely dispersed Muslim ethnic group in Sahel and West Africa. They number between 20 and 25 million people in total across many countries of this region, and they have historically featured a