The Bonobo (IPA: /bə'noʊboʊ/, Pan paniscus), until recently usually called the Pygmy Chimpanzee (and less often the Dwarf or Gracile Chimpanzee), is one of the two species making up the chimpanzee genus, Pan. 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. The Bonobo is endangered, and is found in the wild only in the Democratic Republic of Congo. Along with the Common Chimpanzee, the Bonobo is the closest relative to Humans. Since neither species are proficient swimmers, it is possible that the formation of the Congo River 1.5–2 million years ago lead to the speciation of the Bonobo, which live south of the river, from the ancestors of the Common Chimpanzee, which live north of the river.
German anatomist Ernst Schwarz is credited with having discovered the Bonobo in 1928, based on his analysis of a skull in the Tervuren museum in Belgium that had been thought to have belonged to a juvenile chimpanzee. Schwarz published his findings in 1929. In 1933, American anatomist Harold Coolidge offered a more detailed description of the Bonobo, and elevated it to species status. The species is distinguished by relatively long legs, parted hair on their head, a matriarchal culture, and the prominent role of sexual activity in its society.