Speaking of fish, most people's impression is that fish live in water, which cannot be separated from water. In ancient and mysterious Africa, there is a kind of fish that can survive for 3 to 4 years without eating or drinking without water. Let's take a look together.
African lung fish
The world is so big that there are all kinds of wonders. Africa is a place with extreme water shortage, with drought on the land, and even in some parts of Africa people die of water shortage. It is in this environment that there is still another magical creature that survives. It is one African lung fish.
African lungfish is also called mud fish, which mainly lives in Africa. They are also found in Australia and South America. African lungfish is a fish that feeds meat, usually feeds on fish and shrimps. Generally, the direction of the prey is identified through smell.
African lungfish has become the "indigenous people" of the earth. It appeared on the earth as early as the Devonian era 400 million years ago. It escaped four mass extinctions and has survived to this day. Due to its lack of appearance, it is also called a living fossil.
Why can lung fish survive for so long?
This is to talk about its two "skills"
. Unique respiratory system
Lung fish has two respiratory systems. Ordinary fish usually breathe with their gills. After water flows into the fish's mouth, the water is discharged from the gills. There are many capillaries in the gills, which can absorb oxygen in the water and eliminate carbon dioxide , so as to breathe in the water.
lung fish's gills
lung fish also breathe with their gills when they grow up. As they grow up, their gills will slowly degenerate. At this time, they breathe with their bladder. The bladder of the lung fish is distributed with dense air chambers, and each air chamber is distributed with air sacs. There are also complex tiny blood vessels on the bladder, which is equivalent to people's lungs and can perform breathing circulation. When the air enters the nose, the gas will enter fish bladder through the intestines to conduct gas circulation. Adult lung fish can also use gills to assist breathing. As long as you don't stay in the water for a long time, the lung fish will not be suffocated to death.
: " summer sleep "
When there is sufficient water source, they will live in the water with normal fish, but when the dry season comes, they will drill into the soil and perform "summer sleep", which summer sleep is similar to hibernation. When the last water in the soil evaporates, the lung fish itself will secrete a kind of mucus, which can help the lung fish avoid drying and cracking on the surface.
Must secreted by lung fish
In order to prevent themselves from thirsty and starving, lung fish usually adjust themselves to "standby" mode when they are drought, which lasts for up to half a year. During standby mode, lungfish only sleep in the soil, reducing their metabolism to about 2% of normal times. Do not eat or drink, and can maintain vital signs for 3 to 4 years.
Only when the environment is not so harsh and drought will they emerge from the soil, receive the nourishment of water, and then start foraging.
escaped drought, but did not escape people's "hoe"
Lung fish are buried in the soil, and people found that
Africa during the dry season is very scarce in Africa. Residents who have lived in this land for a long time have also mastered the survival of lung fish.
In order to find food, African residents will bring hoes and come to the nearby dry riverbed, and carefully search for the breathing holes left by lung fish in order to breathe. Experienced people can quickly identify the hiding point of lung fish in just a while, and then dig down the hole and see a large oval mud ball. As long as you gently break the mud ball open, you will see a lively lung fish. If you are lucky, you may be able to directly take the lung fish.
There is another story about lung fish
When building houses, African citizens usually cannot use steel bars and muds due to their limited ability. They use soil to build houses. Generally, lung fish are hidden in the soil. Without the residents paying attention, lung fish is built in the wall by the residents. They wanted to survive the dry season, but people regarded it as a "brick". It's really sad.
lung fish's "house"
lung fish gill breathing and summer sleep modes help them become the only fish in the world that can survive in the soil, and perfectly explain to mankind what is the principle of "survival of the fittest, survival of the fittest, natural selection" is.
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