Xochimilco is an intricate network of natural canals and artificial islands (chinampas) spanning approximately 170 km² in southern Mexico City. The canals are the remnants of what was once an extensive lake and canal system that connected most of the settlements in the Valle de México (Valley of Mexico). These canals, along with the artificial islands known as chinampas, attract tourists and local residents who ride on colourful gondola-like boats called trajineras.
Xochimilco's system of waterways was once the main means of transportation, especially for goods, particularly during the pre-Hispanic period. Today, the canals are fed by freshwater springs, which are artificially supplemented with treated water. This is because water tables continue to decline, while urban expansion and the filling in of canals persist, threatening the survival of the last remaining waterways.
Xochimilco is home to a large number of species, including migratory birds, amphibians, and reptiles. Perhaps the most representative animal found in these waters is the axolotl (Ambystoma mexicanum), a salamander that reaches sexual maturity while retaining its larval form, a phenomenon unique among amphibians. Although primarily aquatic, axolotls have a limited ability to breathe air. They can also regenerate limbs and other body parts, making them the focus of numerous scientific studies. As of 2014, only around 36 axolotls per km² were estimated to remain in the canals of Xochimilco. Updated figures are expected following the 2024–25 axolotl census conducted by UNAM, with results anticipated to provide the most current assessment of the species’ wild population.
Most of the threats to the species stem from habitat loss and pollution, but the introduction of non-native fish such as tilapia has also had devastating effects on their population.
