Police dog trainer Cheng Zhicong interacts with his dog Ka Li in Haikou, south China's Hainan Province, Feb. 9, 2018. Police dog trainers and their dog here celebrate the day of Xiaonian by being together. Xiaonian falls on the 23rd or 24th day of the last month of the Chinese traditional lunar calendar, marking the start of the countdown to Chinese Year of the Dog. (Xinhua/Lei Zhe)