Lake Titicaca is a large freshwater lake located high in the Andes Mountains of South America. It is situated between the countries of Bolivia and Peru and is considered to be one of the most important bodies of water in the region both geographically and culturally. For thousands of years the indigenous peoples of the region have considered the lake to be a sacred site. After their arrival in the 15th century, the Incas came to believe that the lake was the birthplace of the sun and the moon, and that the first Inca emperor emerged from the lake to establish his empire.
Situated on the border between Peru and Bolivia at an altitude of 3,810 meters (12,500 feet), Lake Titicaca is the highest lake in the world that is navigable by large vessels. While it is the second largest lake in South America in terms of surface area, it is the largest in terms of total water volume. The lake runs from the northwest to the southeast for roughly 190 kilometers (120 miles). It is 80 kilometers (50 miles) across at its widest point and reaches a maximum depth of 284 meters (932 feet). Geologically the lake is divided into two parts by the Tiquina Strait: the greater lake (Chucuito) and the smaller lake (Huiñaymarca).
The lake is located on a high plateau, the Altiplano, which includes the hydrological basin of Lake Titicaca, the Desaguadero River, Lake Poopo, and the Salt Lake of Coipasa. The Altiplano is made up of a series of plains and mountainous areas, as well as a wide plateau called the Puna. Lake Titicaca occupies the Northern High Plains, Bolivia’s Lake Poopo the Central High Plains, and the Coipasa and Uyuni salt flats the Southern High Plains. The region’s highest point is Mount Sajama, which rises to 6,542 meters (21,460 feet). The lake was first formed 60 million years ago as a result of seismic activity in the Andes that split the mountain range apart leaving a high, wide depression that eventually filled with water from melting glaciers. Alternating ice ages and warming events continued to alter the topography of the area until the lake attained its current shape and structure as glaciers began melting across the Altiplano yet again during the Holocene glacial retreat some 10,000 years ago.
The lake’s high altitude makes for a somewhat cool but regulated climate. Nocturnal temperatures average 9°C (48°F) most of the year. The lake is fed in equal parts by direct precipitation and rivers that descend from the mountainous plateau that surrounds it. The permanent tributary rivers that feed into Lake Titicaca are, in descending order of volume: Ramis, Coata, Ilave, Huancane, and Suchez. Direct annual rainfall amounts are typically in the vicinity of 1.4 meters (6 feet). The majority of annual water volume (95%) is lost to evaporation rather than from downstream outflows (5%). The lake itself produces a thermal regulating effect which mitigates temperature extremes and allows many plant and animal species to flourish in and along its shores.
The origin of the lake’s name is not completely clear, although locals believe that the shape ofthe lake (when seen from above) resembles a puma snaring a rabbit. In fact, the name Titicaca—derived from the local indigenous Aymara language—means “rock of the puma,” which gives some credence to this theory.
The cultural history of the lake dates back thousands of years. The first people to inhabit the Titicaca basin arrived around 8,000 years ago. Archaeological evidence reveals the earliest settlements were established by roaming groups of hunter-gatherers. Over the next 5,000 years these temporary encampments gave way to more permanent farming communities in the surrounding hills. Around 2,000 years ago farmers began creating terraced sections in the low mountains above the lake, carving out flat areas reinforced with stone walls. Terracing allowed farmers to convert steep hillsides otherwise unsuitable for growing crops into manageable and arable land. The creation of hillside terraces helped deepen the available soil, curb erosion, and increase moisture prevention by reducing runoff, all of which were significant improvements when relying on rainfall rather than irrigation to water crops. Evidence of these vast human-made patchworks can still be seen in satellite imagery of the region today.
As the Incan empire expanded throughout the Andes in the 15th century, it incorporated the Altiplano into its territory, including Lake Titicaca. The Inca also adopted the myths and belief systems of the local population as they settled in the region. Although Cusco was the capital ofthe Incan empire at the time, the Inca came to believe that Lake Titicaca was the center of the known cosmos and the source of Andean creation. Two islands in the lake whose religious importance originated with the Tiwanaku people—the Island of the Sun and the Island of the Moon—became Incan sacred sites. One Inca legend describes how the god Viracocha, after emerging from the lake’s waters, created the sun, moon, stars, and the first humans. When Incas died it was thought that their souls returned to the origin of all things, which meant a spiritual reunification with the waters of the lake. Another legend outlines how the sun god directed his sons, who emerged from the lake’s depths, to civilize the Andean people and encourage them to build an empire to honor the ancient deities.
One of the earliest and most significant settlements around the lake was the city of Tiwanaku, the eventual capital of an extensive regional empire that predated the arrival of the Incas by more than a millennium. Originating around 200 BCE, the city grew to encompass an area of roughly 4 square kilometers (1.5 square miles), and at its peak in the 7th century CE had a population of around 10,000 people. Archaeologists believe the city and its population collapsed sometime around the year 1000, possibly due to drought or other climate-induced hardships. The remains of Tiwanaku represent one of the largest such sites in all of South America and include temples, dwellings, raised ceremonial platforms and courtyards, large earthen mounds and paved terraces, pyramids, and stone monuments. The Gate of the Sun, a monolithic archway carved from a single piece of rock, stands nearly 3 meters (10 feet) tall and weighs an estimated 10 tons. The top of the arch is covered in carvings believed to be astronomical notations relating to the position of the sun, moon, and other celestial bodies.
Scientists have determined that the green andesite stone used for the construction and decoration of ceremonial sites throughout Tiwanaku did not originate there but came from a quarry 90 kilometers (56 miles) across the lake. In the early 2000s, a group of archaeologists from the Penn Museum in the United States traveled to the lake to see if they could determine the method by which such large stones, some weighing as much as nine tons, were transported from the quarry to Tiwanaku. An overland route would have been impossible at the time, so the only other possibility would have been transport by boat. The high Andean plateau lacks forests and is covered almost entirely in grasslands. Therefore, the construction of wooden boats would not have been possible. However, the shores of the lake are populated with an aquatic reed called totora, the only available material for building watercraft. The local Aymara people who still live around the lake have maintained an ancient tradition of fashioning sailing boats from bundles of totora tied together with rope. Enlisting the expertise of these locals, the researchers spent two months helping to construct a large reed boat that, they hoped, would be capable of carrying an enormous stone across the lake and thus demonstrate how, in theory, the ancient people of Tiwanaku were able to populate their city with stones from far away. Once the boat was finished, the team sailed it to the quarry, loaded a 9-ton stone onto the boat with the help of more than 40 people, and successfully returned with it to Tiwanaku, proving that such a feat was possible.
The Aymara are not the only people who have used the aquatic reeds to keep afloat on the lake. The Uros people maintain a series of artificial islands in the western part of the lake crafted from the same reeds. Believed to be the lake’s first inhabitants, the Uros were able to evade the threat posed by the expanding Inca empire by living on their own floating islands in the middle of the lake. Their descendants still live in communities built upon these floating oases. There are estimated to be between 60 and 70 artificial islands in the lake at any one time. Some wear out and need to be rebuilt, while others join together to form even larger floating villages.
Peru declared Lake Titicaca a National Reserve in 1987, signaling a desire to preserve the lake’s valuable and fragile natural resources, unique biodiversity, and the cultural traditions of its indigenous inhabitants. In 2016 the presidents of Peru and Bolivia agreed to fund cleanup efforts to combat the growing threat from pollution. An increasing population along the lake’s shoreline has outpaced water treatment efforts, and industrial effluent is often channeled directly into the lake creating a toxic hazard for local inhabitants and threatening more than 500 native aquatic species, including the Titicaca water frog. Titicaca has been on the United Nations Educational, Scientific and Cultural Organization’s tentative list as a World Heritage site since 2005.
Lake Titicaca serves as a living historical monument replete with native inhabitants who live as their ancestors did, speaking the same language, practicing the same traditions, and honoring the same gods. Visitors to the lake are treated not only to stunning Andean views but also to a rich cultural heritage dating back more than 2,000 years.
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