Disclaimer: Following is a speculative essay. I have no formal education in biology or archaeology and I cannot comment on the subject in any professional capacity. It is merely an intriguing thought, nothing more. I just wanted to put it out there; I am sure that a professional would be able to answer the question I am posing.
After reading The World Without Us by Alan Weisman , an intriguing thought occurred to me: If there had been other "intelligent" species before us, would they have left any trace of their existence behind them?
The World Without Us answers a thought-provoking question: If the human species were to disappear from the face of the world today - just disappear, nothing violent, as if we packed up and went elsewhere to the last person - what would the planet look like afterwards? Weisman draws inferences from real life events where people did leave settled towns ın a hurry, such as Pripyat near Chernobyl and Famagusta. He also uses engineering data to estimate how long many structures would stand and what would happen to them eventually.
What I found striking is that all of our structures would disappear in 5 million years. Now consider the timeline of the five previous big extinction events:
- Cretaceous-Paleogene extinction event, 66 million years ago
- Triassic–Jurassic extinction event, 200 million years ago
- Permian-Triassic extinction event, 251 million years ago
- Late Devonian extinction event, 375-360 million years ago
- Ordovician–Silurian extinction event, 450-440 million years ago
This is suspicious: Is this really a coincidence? There seems to be a lot of evidence pointing towards a human caused mass extinction of megafauna. Hence my question: If one or two of the previous extinction events were caused by a similar complex society created by an invasive species like us, would that leave any archaeological evidence?
Note that we do have a lot of archaeological evidence concerning the tools of the previous human societies. But there are relatively new events: The rise of settled cities is approximately 10 thousand years old - that is a mere 0.01 million years. Relatively advanced tool-making is approximately 0.05 million years-old. The homo sapiens species goes back to almost 0.2 million years, and the earliest evidence of tool use goes back to approximately 3 million years, similar to the earliest species of the homo genus. Note that at this point, the tools are very crude. Therefore, all of our archaeological evidence would span 3 million years at the largest. Furthermore, most of the archaeological evidence would be concentrated in the last 0.01 million years. Furthermore, most of it would be concentrated in the urban areas.
So here is the apex: Consider a question similar to Weisman's original question: Imagine that we become extinct due to the Holocene extinction in the next few ten thousand years. This is still a very small time period, much more precise than our estimates of the previous extinction events' timelines. 50 million years after that, another species creates a complex society and develop archaeology. Would they be able to find any archaeological remains of our species? And if the answer is no, can we be certain that this did not happen in the few thousand years before us?