The Lungfish also known as “salamanderfish”, is a type of freshwater fish famous for its ability to live on land, without water, for months on end, and sometimes even years.
As its name suggests the fish have a highly evolved respiratory system that can take oxygen straight from the air, similar to land animals. However, few species of Lungfish are so used to breathing air that they gradually lose the function of their gills as the fish reach adulthood. Whereas they still live in water, and their requirements to frequently come up to the surface for fresh air. Certain species can create mild electric discharges. This could be useful for navigation, communication, or prey detection.
These fishes are quite fascinating creatures that have evolved to withstand extreme circumstances. Some species demonstrate parental care, which is uncommon in fish. They safeguard their eggs and young, which is similar to what more advanced vertebrates do.
The fish can even drown if kept underwater for a long time. Lungfish have elongated bodies, just like eels, with thread-like pectoral and pelvic fins which they use to swim and crawl along the bottom. The fish usually inhabit shallow waters, such as swamps and marshes, but they’re also found in bigger lakes. The lungfish feeds on fish, insects, crustaceans, worms, molluscs, amphibians, and plant matter. They have an intestinal spiral valve rather than a true stomach. Normally, fish excrete nitrogenous waste as ammonia directly into the water. The lungfish can be extremely long-lived.
Moreover, when there’s water, the fish acts like any other fish, swimming in the waters and eating small fish and crustaceans on the bottoms of ponds and streams. However, when the dry season comes, the fish burrows itself deep into the mud, digging out a path by taking mud into its mouth and forcing it out its gills. Thus after the fish has touched a comfortable depth, the fish will stop digging and secrete a mucous out of the skin that hardens to form a protective cocoon around it.
Though only the mouth is left showing for breathing. Therefore, for its long hibernation, the lungfish will greatly decrease its metabolism and live off the muscle tissues in its tail. Because once the water returns and the mud soften, it will wriggle out of its burrow. Furthermore, some reports claim that the fish can stay underground in dried mud for as long as four years. The lungfishes are found only in Australia, Africa, and South America. In Africa, the people use to eat lungfish that would often dig out the fish from dry soil. The fish is said to have a strong taste and is not enjoyed by all. Lungfish are known as “living fossils” because their ancestors date back hundreds of millions of years. They provide important insights on the evolution of vertebrates.
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