Here's why:
* Early Conservation Efforts: Conservation efforts for giant pandas were still in their very early stages in the 1920s. There was no organized tracking or census of their population.
* Limited Access: The areas where giant pandas lived were remote and difficult to access, making population estimates extremely challenging.
* Lack of Research: Scientific research on giant panda populations was still in its infancy at that time.
However, we can say that the giant panda population was already facing significant threats:
* Habitat Loss: Deforestation and human encroachment into their natural habitat were already a major concern.
* Hunting: Giant pandas were hunted for their fur and other body parts.
While we don't know the exact number, it's safe to assume that the giant panda population was already declining significantly by 1920.