A wildlife conservation worker measures the weight of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)

A wildlife conservation worker checks the oral cavity of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)

A wildlife conservation worker checks the ear of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)

 wildlife conservation worker checks the oral cavity of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)

A wildlife conservation worker measures the abdominal circumference of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)

Wildlife conservation workers measure the chest circumference of an Asian elephant named "Xiaoqiang" at the Asian Elephant Breeding and Rescue Center in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, March 6, 2021. The Asian elephants, which are under first-class national protection with a population of less than 400 in China, are mainly found in Yunnan. Wildlife conservation workers at the Asian Elephant Breeding and Rescue Center have dedicated themselves to improving the welfare of the species. (Xinhua/Jiang Wenyao)