Have you ever thought about swimming in the wild in winter? Maybe the biting cold has deterred you for a long time. So, can fish survive in the cold water environment for a long time? In fact, most fish have frozen into "popsicles" in - 1 ℃ water. But there is a kind of fish called cod, which lives in the extremely cold Arctic all year round, but they can swim freely in the water of - 1.87 ℃. Why don't Arctic cod freeze to death?
We know that fish are cold-blooded animals, that is, their body temperature can change with the change of ambient temperature. Arctic cod live in cold water all year round. In order to adapt to this environment, they have derived a series of adaptation mechanisms, the most important of which is the formation of thick fat in the subcutaneous layer of the fish. Fat has a good resistance to cold water, which is why Arctic cod can survive in extremely cold environments. Moreover, as a variable temperature animal, the body temperature of fish is basically the same as that of the outside world, which saves the energy required to supplement heat, so they can not only survive, but also live freely.
In addition, the research results of scientists in recent years show that there is another important reason why Arctic cod can't freeze to death - the existence of antifreeze protein in serum.
Antifreeze protein is a special specific protein, which exists in fish serum in cold sea area. The reason why it has antifreeze effect is that antifreeze protein can form a relatively flat surface to identify the surface of ice. Once it is adsorbed to the surface of ice crystal, the new ice layer must grow along the gap without protein, resulting in the curved surface of ice crystal, and the local freezing point will drop, so as to reduce the freezing point of water, so as to prevent the freezing of body fluid. Due to the special structure on the surface of antifreeze protein, ice crystals cannot grow along its surface, so it can avoid being swallowed by ice crystals and losing its activity. Arctic cod serum, there is this so that it will not freeze to death of the "protective god".