Post #13856

Do fish drink water? An unexpected answer to a child's question You probably won't believe me now, but the answer is both yes and no. Some fish gush water down their throats, while others, on the contrary, do their best to avoid getting moisture into their bodies. After all, it all depends on the conditions in which the organism lives. The easiest way to explain aquatic-fish relationships is with squamates that live in the World Ocean. Since their bodies are less salty than the surrounding water, they face a problem: the moisture in their bodies is constantly trying to go AWOL, it is being drawn out by the salt of the ocean. And so they drink, and they drink a lot. After all, they need to constantly pump themselves with water and, at the same time, filter out excess salt with the help of their kidneys almost without interruption. In freshwater fish the situation is completely opposite. Their body is much saltier than the surrounding water, so it itself absorbs water from... water against their will. And, naturally, in such conditions, only a complete suicidal person can drink additional water - after all, you are constantly swelling like a sponge. Therefore, all adequate river fish pass water through their gills, but prefer not to drink it. And at this time their kidneys are plowing like hell, trying to retain salt inside the body and at the same time rid it of excess moisture. And cartilaginous fish (sharks, rays, chimeras) fared best, because the salinity of their body is approximately equal to the salinity of the water. Therefore, for them, she is not an aggressive environment, but a loyal friend. If for some reason there is too little water in the body, it will simply be automatically replenished through the integument. There is too much - the excess will be sucked out by the ocean. That’s why their kidneys are noticeably more primitive; they can afford to cheat. What moral can we take away from this story? First: take care of your kidneys, without them you will be nowhere in maintaining the water-salt balance. Second: sharks are still cheaters. Maybe that's why they haven't changed much over the last couple of hundred million years? Author: Yaroslav Ilyin 🏀 Hit the hoop and get an NFT gift — https://t.me/BasketbolX_bot