Can someone explain this cold joke?

A joke a long time ago, seemingly incomplete, probably means that after the orangutan finished a series of actions, it caused a huge sensation, and everyone in the scientific community did not understand it after decades of research. After many years, it seems that a zoo keeper revealed the action that the scientific community has been studying for a long time: damn, flying too fast, I didn't see anything clearly.

The former sent orangutans to investigate and satirized human stupidity, while the latter satirized human complex thinking.