The Orinoco is supposed to have 436 tributaries, of which, among the largest, the Caroni-Paragua, Aro, Caura, Cuchivero, Suapure, Sipapo and Ventuari have their sources in the Guiana highlands; the Suata, Manapere and Guaritico in the northern sierras; and the Apure, Uricana, Arauca, Capanaparo, Meta, Vichada and Guaviare (the last three being Colombian rivers) in the llanos and Andes.