Lake Titicaca, a vast freshwater expanse, sits high in the Andes Mountains, straddling the border between Peru and Bolivia. It is widely recognized as the world’s highest navigable lake, resting at an elevation of approximately 3,810 meters (12,507 feet) above sea level. This immense body of water, covering an area of around 8,300 square kilometers (3,200 square miles), is also one of South America’s largest lakes by surface area. Its cold, oxygen-rich waters and high-altitude environment contribute to a unique ecosystem that supports diverse animal life.
Fish Species of Lake Titicaca
Lake Titicaca is home to a distinctive array of fish species, many of which are endemic to its waters. The native fish fauna is primarily composed of two genera: Orestias, commonly known as killifish, and Trichomycterus, a type of catfish. There are at least 23 recognized species of Orestias found within the lake’s basin, and two species of Trichomycterus catfish. These native fish thrive in the lake’s specific conditions, with Orestias species consuming insects, algae, and small invertebrates.
Native fish populations have been significantly impacted by introduced non-native species. Rainbow trout (Oncorhynchus mykiss) and Argentinian silverside (Odontesthes bonariensis), introduced mid-20th century, have become established in the lake. These predatory species outcompete and prey upon the native Orestias and Trichomycterus species. For instance, the Titicaca Orestias (Orestias cuvieri) became extinct due to competition and predation from introduced trout and silverside.
Amphibians of Lake Titicaca
Among the amphibians inhabiting Lake Titicaca, the Titicaca Water Frog (Telmatobius culeus) is a specialized species. This large frog is fully aquatic, living exclusively within Lake Titicaca and its associated tributaries. It can reach a snout-to-vent length of 7.5 to 17 cm (3.0–6.7 in) and weigh up to 0.4 kg (0.9 lb).
The Titicaca Water Frog’s loose, folded skin creates an increased surface area. This adaptation aids respiration, allowing the frog to absorb oxygen directly from the cold, oxygen-rich water, compensating for its relatively small lungs in the high-altitude, low-atmospheric pressure environment. The frog’s skin is highly vascularized, rich in blood vessels, further enhancing its ability to respire aquatically.
Birdlife of Lake Titicaca
Lake Titicaca and its surrounding wetlands provide a habitat for a diverse array of bird species. Over 60 bird species have been recorded in the region, making the lake an important avian sanctuary. A unique inhabitant is the Titicaca Grebe (Rollandia microptera), an endemic and flightless bird found only in the lake’s waters. This grebe relies on the dense totora reed beds for nesting and foraging, diving for small fish and aquatic invertebrates.
Other prominent bird species include the Andean Gull (Chroicocephalus serranus) and various duck species. Flamingos, such as the Andean Flamingo (Phoenicoparrus andinus) and James’s Flamingo (Phoenicoparrus jamesi), are seasonally present, feeding on algae and small aquatic creatures. The Puna Ibis (Plegadis ridgwayi), with its metallic plumage and curved beak, forages in the wetlands, consuming insects, mollusks, and small crustaceans.
Other Aquatic Invertebrates
Beneath the surface of Lake Titicaca, aquatic invertebrates form a fundamental community that serves as the base of the lake’s food web. They are crucial food sources for fish and birds. The lake supports diverse crustaceans, including 11 endemic Hyalella amphipods.
Mollusks, snails, are also present, with 24 species, many of which are endemic to the lake. They inhabit various depths and substrates. Insect larvae also contribute to the invertebrate community. Chironomid (non-biting midge) larvae are a permanent and sometimes abundant component, playing a significant role in the lake’s secondary production. These invertebrates graze on algae and detritus, converting organic matter into a form digestible by larger aquatic animals.