As many as 250 ethnic groups have been distinguished and named. The most numerous people are the Kongo, Luba, and Mongo. Although 700 local languages and dialects are spoken, the linguistic variety is bridged both by the use of French and the intermediary languages Kikongo, Tshiluba, Swahili, and Lingala.
The Bonobo (/bəˈnoʊboʊ/ or /ˈbɒnɵboʊ/), Pan paniscus, previously called the Pygmy Chimpanzee and less often, the Dwarf or Gracile Chimpanzee, is a great ape and one of the two species making up the genusPan. The other species in genus Pan is Pan troglodytes, or the Common Chimpanzee. Although the name "chimpanzee" is sometimes used to refer to both species together, it is usually understood as referring to the Common Chimpanzee, while Pan paniscus is usually referred to as the Bonobo.
The Bonobo is endangered and is found in the wild only in the Democratic Republic of the Congo. Along with the Common Chimpanzee, the Bonobo is the closest extant relative to humans. Since the two species are not proficient swimmers, it is possible that the formation of the Congo River 1.5–2 million years ago led to the speciation of the Bonobo. They live south of the river, and thereby were separated from the ancestors of the Common Chimpanzee, which live north of the river.