Jean Yiqi Yao is a zoologist who works in the French National Museum of Natural History. He invested too much in his work, and his hair lost a lot in middle age. Because animal domestication is one of his important research topics, what he often says is: "It's hard to imagine what the world would be like without cats, dogs, pigs, cattle and sheep?" This is indeed a question that challenges people's imagination, especially before humans created them. These animals closely related to human life do not exist in nature! So, how were they created? Jean Yiqi Yao and other zoologists made detailed investigations all over the world. At the same time, they went upstream along the history of mankind, dating back to that wild era more than 10,000 years ago. 1.8 million years ago, our ancestors lived a nomadic life, and their food and clothes came from bison and reindeer. /kloc-For more than 0.0 million years, the cold period and the hot period have been alternating. At this time, the earth is experiencing the last great cooling, the rivers are about to freeze, the days are getting shorter and shorter, and all living things will be subjected to a cruel survival test. Wolves, like people, have food shortages. In fact, these two populations are very similar: they are both powerful predators, both at the top of the food chain, both have complex group structures, and both catch the same prey on the same land. Man and wolf, competitors, are destined to meet. But this does not seem to be a fair competition. Because people can make tools and kill prey from a distance. The wolf finally chose to quit. However, after catching the prey, humans will not take all the prey away. They will leave the entrails of their prey and trunk parts that other tribes don't eat or use. This allows wolves to enjoy the rest of the food after they leave. From 20000 BC to 15000 BC, the earth's temperature began to rise sharply. With the end of the ice age, famine has become a thing of the past, and food has become rich again. The ice sheet that prevented human migration from Asia to Europe gradually moved northward, and the migration route of human beings became more open and common. At the same time, some wolves also quietly followed the human migration team and fully enjoyed the human remains. This is the origin of the first domesticated animals. Some hunter-gatherer tribes, such as the ashur Indian tribe in the Amazon basin, still retain the tradition of breastfeeding small animals. This way can quickly enhance the feelings between animal orphans and human beings. Perhaps this has also promoted the rapid domestication of wild animals. On the contrary, the ancient Romans believed that their ancestors were orphans raised by wolf milk. It took only 50 generations from wild wolves to the first batch of German shepherd dogs. 654.38+0.2 million years ago, the German shepherd dog was very similar in appearance to its wild ancestors, but obviously smaller in size and more docile in character. These changes are partly due to their reduced activities and corresponding reduced food intake. But the main reason is that the change from natural environment to human environment has greatly changed their hormone secretion. They no longer hunt. Their first task is to defend their homes and give an alarm when they are in danger. In addition, clean up the leftovers. If the German shepherd is still wild, humans will kill it. By killing fierce individuals and keeping docile individuals, our ancestors subconsciously completed a process of "selection", making the habits, appearance and even genes of the first generation of dogs more suitable for human society. There is a little genetic difference between the German shepherd and the wild wolf, that is, German shepherd will make a conscious sound, they can understand some gestures and communicate with human beings to a certain extent. The researchers conducted a series of tests on dogs and wolves. The results show that although the experimental wolf has received a lot of training, it still can't understand its master's intention. It will only work hard by itself, but the dog will communicate with people and ask for help with actions, sounds and expressions. Therefore, the first criterion for researchers to judge early human domestication of wolves is the ability to communicate with others. People who transformed wolves to create the first dog may not realize that they have created a highly breeding race. Decades later, more than 300 kinds of dogs appeared on the earth. Under the influence of human beings, those truly fertile dogs began to differentiate into different kinds.