The Uru or Uros (Qhas Qut suñi) are an indigenous people of Bolivia. They live on a still growing group of about 120 self-fashioned floating islands in Lake Titicaca near Puno. They form three main groups: the Uru-Chipaya, Uru-Murato, and Uru-Iruito. The Uru-Iruito still inhabit the Bolivian side of Lake Titicaca and the Desaguadero River. The indigenous Urus have darker skin than their neighbours Aymaras and Quechuas. According to legend, the Uru descend from a people that spoke the Puquina language. While most of the Uru have shifted to Aymara and Spanish, two people still spoke in 2004 the nearly extinct Uru language, which is closely related to the Chipaya language. The Uru considered themselves the owners of the lake and water. According to the legend, Uru used to say that they had black blood, because they did not feel the cold. They historically called themselves Lupihaques, "sons of the Sun". Although the Uru language is nearly extinct, the Uru continue to maintain their identity and some old customs. The purpose of the island settlements was originally defensive; they could be moved if a threat arose. The largest island retains a watchtower, as do most smaller islands. The Uru traded with the Aymara tribe on the mainland, intermarrying with them and eventually abandoning the Uru language for that of the Aymara. About 500 years ago they lost their original language. When conquered by the Inca empire, they had to pay taxes to them, and often were enslaved. The Uru use bundles of dried Totora reeds to make reed boats (balsas), and to make the islands themselves. The larger islands house about ten families, while smaller ones, only about thirty meters wide, house only two or three families. The islets are made of multiple natural layers harvested in Lake Titicaca: The base is made of large pallets of floating Totora roots, which are tied together with ropes and covered in multiple layers of totora reeds.