The Heath River, which runs from the Andes surrounding Lake Titicaca northwards to the Madre de Dios River, marks the natural border between Peru and Bolivia. The Eja Sonene indigenous community lives in the area. They are an ethnic group belonging to either the Tacana-speaking Arawak, who migrated from the west or those of Pano origin, who originate from the lower reaches of the Madeira River.