The Zarma people are an ethnic group predominantly found in westernmost Niger. They are also found in significant numbers in the adjacent areas of Nigeria and Benin, along with smaller numbers in Burkina Faso, Ivory Coast, Ghana, Togo, and Sudan. In Niger, the Zarma are often considered by outsiders to be of the same ethnicity as the neighboring Songhai proper, although the two groups claim differences, having different histories and speaking different dialects. They are sometimes lumped together as the Zarma-Songhay or Songhay-Zarma. The Zarma people are predominantly Muslims of the Maliki-Sunni school, and they live in the arid Sahel lands, along the Niger River valley which is a source of irrigation, forage for cattle herds, and drinking water. Relatively prosperous, they own cattle, sheep, goats and dromedaries, renting them out to the Fulani people or Tuareg people for tending. The Zarma people have had a history of slave and caste systems, like many West African ethnic groups. Like them, they also have had a historical musical tradition. The Zarma people are alternatively referred to as Zerma, Zaberma, Zabarma Zabermawa, Djerma, Dyerma, Jerma, or other terms. Zarma is the term used by the Zarma people themselves. The estimates for the total population of Zarma people as of 2013 has been generally placed over three million, but it varies. They constitute several smaller ethnic sub-groups, who were either indigenous to the era prior to the Songhai Empire and have assimilated into the Zarma people, or else are people of Zarma origins who have differentiated themselves some time in the precolonial period (through dialect, political structure, or religion), but these are difficult to differentiate according to Fuglestad. Groups usually referred to as part of the Zarma or Songhay, but who have traceable historical distinctions include the Gabda, Tinga, Sorko, Kalles, Golles, Loqas and Kurtey peoples. The Zarma language is one of the southern Songhai languages, a branch of the Nilo-Saharan language family.