The high-altitude lake in the Andes that is the natural habitat of the Titicaca water frog is Lake Titicaca.
The Titicaca water frog, Telmatobius culeus, is a fully aquatic frog native to the Lake Titicaca basin on the border of Peru and Bolivia. Unlike many frogs, it spends essentially its entire life underwater, where it has adapted to the lake's cold, high-elevation environment.
Its loose, heavily folded skin gives the frog an unusual appearance and greatly increases the surface area available for absorbing oxygen from the water. This adaptation is especially important because Lake Titicaca's high altitude means the water contains less dissolved oxygen than lowland lakes. The frog also has large lungs, but skin respiration is central to its survival.
Lake Titicaca is often confused with other famous Andean lakes, including Lake Junín and Lake Poopó. Those lakes are in the same broad region, but they are not the defining habitat of the Titicaca water frog. Pollution, introduced trout, habitat degradation, and collection have all threatened the species.