At the beginning of the 20th century, the Kaibab Forest in northern Arizona, USA, was still lush with pines and firs and full of vitality. There are about 4,000 deer in the forest, and the ferocious and cruel wolves are the deer’s biggest enemies. 　　 U.S. President Theodore Roosevelt wanted to effectively protect the deer in the Kaibabo Forest and breed more. He declared the Kaibab Forest a national hunting preserve and decided that the government would hire hunters to go there and eliminate wolves. 　　 The sound of gunfire echoed through the forest. Under the cold muzzle of the hunter, the wolf screamed one after another and died.…