Once there were fish Devonian pandericht and tiktaalik, from which the first tetrapods are believed to have originated. Scientists found that due to external environmental conditions, they had to move to land. However, the way they moved on the ground remained unclear. First of all, due to the lack of examples of modern land fish that would be similar to the ancient Devonian fish. The study of this issue was undertaken by Alexander Kuznetsov from the Paleontological Institute. A.A. Borisyak of the Russian Academy of Sciences.
For the study, the scientist bought four freshwater amphibiotic fish from southern Vietnam, including the Monopterus rice eel, Anabas creeper, Clarias catfish and Channa snakeheads. Then, for one to three days, he observed the peculiarities of the movement of fish on wet clay. It turned out that all of them (the largest was a snakehead with a length of 1.5 m and a mass of 1.2 kg) in a similar way, that is, “jerking” with small interruptions. The main conclusion of the study was that in order to move on land, fish need only an organ of air respiration, that is, an analogue of the lungs. In addition, these fish have swimming muscles located on the sides of the body, which acts as a “motor”, helping to move along the ground.