Today, people often know that tigers have always lived in the mountains, and they do not know the history of their withdrawal from the plains. During the Tang and Song dynasties, with the transfer of the economic and cultural center from the Yellow River basin to the Yangtze River basin, a large number of northern population moved southward and the South China tiger completely withdrew from the plain area. After that, idioms such as diverting the tiger from the mountain, letting the tiger return to the mountain and sitting on the mountain to watch the tiger fight showed that people had mistakenly regarded the tiger as a mountain species at that time and did not know that the tiger was forced up the mountain because of human activities.
The most accurate summary of the gist of this passage is that it describes the history of tigers retreating to the mountains with human activities.