Looking around, the rivers in Alaska are full of salmon, and some of them are washed to the banks, laying golden eggs and then dying. Why do thousands of salmon go upstream every year and return to their hometown of birth regardless of their lives?
This has a lot to do with the life habits of salmon. It is a cold-water migratory fish that migrates upstream to spawn. It has a fierce temperament and preys on small fish such as herring and herring for a living. Every time it comes to spawning season, they swim into the river at risk for the sake of racial reproduction.
They will encounter unknown dangers in their migration. A shocking picture is that salmon rushes to the opposite stream while the river overflows the road. One or two failures will not make them shrink back. Some fish managed to climb onto the road, but were crushed to death by passing cars. Other salmon, regardless of the danger, rushed to the stream across the road.
The salmon went upstream in order to return to their birthplace and lay eggs to breed the next generation. At this time, the salmon was exhausted and the whole body was dim. When you enter the fresh water reproduction period, you will no longer eat, but only rely on the nutrients stored in your body to maintain your life. At first, they frolic in the clear stream, and then gather in small stone pits in groups to lay eggs there.
After laying eggs, the salmon will die slowly. The river is covered with thousands of salmon carcasses, and their offspring will start to hatch here. The newly hatched fish return to the sea along the river. After three or four years of growth, they return to their birthplace to lay eggs after maturity, and so on.