Other animals have tails. Why did the human tail disappear in evolution?

Because in the process of human evolution, the role of the tail is getting smaller and smaller, so it finally disappeared directly.

First of all, the role of the tail

Generally speaking, the tail is used to keep the body balanced, such as cats and monkeys. They are animals with very strong balance bars. For them, tails play a very important role. When cats fall from the sky, they will change their body posture in the air with their tails to ensure that they can protect themselves from harm when they land. And if the cat's tail is injured, it will have a great impact on their balance. Someone has done an experiment before to let a cat walk through a space full of obstacles. A cat with a healthy tail can do it easily. Even if the obstacles are very dense, the cat can avoid them directly. And if it is a cat with a broken tail, they will directly hit these obstacles. This shows the importance of tail.

Second, why did the tail disappear?

In other words, the main ability of the tail is to keep balance, while human beings gradually walk upright in the process of refinement. And what is used to keep balance has changed from the tail to our hands. Therefore, the tail gradually lost its function. In thousands of years of evolution, human beings have no tail. This is also the result of preferential evolution. This can also be seen from apes. Apes used to have a long tail, but in the process of slow evolution, the ape's tail began to evolve slowly. At present, the tails of apes are only a little short, and in the future, their tails are likely to be completely degraded. Apes can reach a semi-upright state, and their center gradually becomes the center of the body. In this way, they don't need to rely on their tails to keep their balance, and their tails will slowly disappear.

Actually, it's good to have no tail. If we have a tail, we still need to sleep on the pillow every day, otherwise it will crush our tail.