In the history of the universe, human beings and nonhuman animals are the significant components of ecosystem which has evolved for millions of years. As time went by, both humans and animals developed their skills and formed their communities. The similar process indicates that all beings are experiencing subjects of a life, and they are capable of suffering and have the consciousness of what they do, feel, and want. On this basis, some might argue that both humans and animals are worthy of moral consideration. It is also controversial to determine whether humans and animals enjoy equal moral rights. However, one of the most essential differences between humans and animals is the ability to self-reflect. We, human beings, are able to reflect on ourselves and avoid making mistakes which are morally wrong. Therefore, I firmly believe that human beings have a greater moral priority over nonhuman animals.