人类的第一个朋友，是在孤独中陪伴我们的那道温暖的光。德古拉元年2血的背叛

　　He has shared our lives for 20,000 years. Along the way, he has helped us find food, kept our livestock, protected us from our enemies, guided us in extreme conditions, and saved us from peril. Now, he comforts us, relieving loneliness and helping us cope with old age. How did dogs come about?