The ongoing Yangtze finless porpoise expedition started on September 19 and has arrived at Poyang Lake. How do the experts carry out the inspection? What devices do they use? Let's join the Yangtze finless porpoise specialists on board and have a look at this fascinating animal nicknamed the "smiling angel."

The Yangtze finless porpoise, which is under top-level state protection, is an important indicator of the Yangtze River ecology. It is also an endangered species, with only 1,012 in China, according to the 2017 survey.

CGTN launched "The Great Rivers of China" series, introducing the seven major water systems in China from the perspectives of natural geography, local customs and significance to the social and economic development of the regions along their routes. The Yellow, Yangtze, Songhua, Haihe, Huaihe, Pearl and Lancang rivers will be featured.