Lungfishaka cá Salamanderfishis a freshwater fish capable of living on land without water for months, even years.
This type of fish has appeared since ancient times, it is estimated that the first fish appeared on earth from about 419.2 million – 393.3 million years ago, and after 4 extinctions still survived resiliently.
This fish builds its own cocoon when the dry season comes.
In fact, lungfish have 3 genera and 6 subspecies and are divided according to place of residence, such as lungfish African lungfish, American lungfish and Australian lungfish. Adult lungfish will weigh 10kg and be 1.25m long. In there, Victoria lungfish is the largest African lungfish species today, can be up to 2m long.
The temperature in Africa is high all year round, there are no four seasons, and it is mainly dry. In particular, the dry season in Africa is very harsh, usually lasting at least 4-5 months. This causes all rivers and lakes here to dry up. To be able to survive, lungfish have evolved “regime summer sleep” with an extremely unique respiratory system.
Lungfish have a highly developed respiratory system that can get oxygen from the air like other land animals. They live underwater when they are young and must rise to the surface to breathe air regularly. Once mature, they can live on land for a year, and can even drown if they are kept in water for too long.
Summer hibernation mainly occurs in tropical animals. Victorian naturalists sought to transport African lungfish halfway around the world to England and America to observe their physiology. Since then, technological advances have helped reveal the cellular and genetic processes behind the lungfish’s summer sleeping behavior. Because they do not have legs to move on land and can be isolated from other environments when the water dries up, African lungfish have evolved to exist in a dormant state in the mud until water returns. .
Induction, the first stage of hibernation, lays the groundwork for spending the next several months underground. In 1986, researchers pointed out a series of signs that promote summer sleep including dehydration, hunger, increased air breathing and stress. Additionally, changes in salinity and the composition of dissolved compounds (such as calcium and magnesium) in the surrounding water signal that the river is drying up. It is possible that the gills play a role in helping to sense the amount of water in the fish’s body.
With signs around them that the environment is warming and drying, lungfish burrow into the mud, using their mouths and heavily muscled bodies. Then, they retreat into the burrow, curl up their long bodies, covering themselves in a large amount of secreted mucus. After hardening, the mucus forms a waterproof cocoon, with only a narrow gap connecting to the water surface to help the fish breathe air through its lungs.
Their fins are very stiff to move on land easily.
Lungfish have a long body similar to an eel, and strong pectoral and abdominal fins, helping them move easily on land. They usually live in shallow waters, such as marshes and swamps, but are sometimes found in large lakes.
