The Neanderthals had an intelligence that almost became a civilisation. From 300,000 bc to 30,000 bc-they had a society in europe, used tools and fire. They buried their dead and painted caves with pictures. They became extinct around 20,000 years ago.
Humans have had a flourishing civilisation for about 5000 years- and here we are, on the moon, in space, nuclear power etc.
Chimpanzees have used tools for 100’s of years- straws to fish insects out of holes, stones to smash nuts open etc.
Three branches of the same species tree. Humans and Neanderthals are like twins genetically, Gorillas and chimps are brothers, and other primates are close cousins.
Here we seem to have several minor branches from the same main species branch that use intelligence as a primary tool of survival and have flourished because of it over the space of a 1/2 a million years.
It is clear that intelligence is a primary survival tool for all species. Bees use a form of intelligence to find pollen/communicate for example.
Shark, Tuna, Dolphin arrive at the same physical design for optimal survival in the ocean. There have been several iterations in the fossil record of the sabre tooth tiger.
Therefore, to believe humans have created the first intelligent civilisation in 4 billion years is unreasonable from a statistical perspective.
It is quite likely that in the past 4 billion years there have been other species that have reached a similar level of intelligence to humans before going extinct.
we base our assumption that humanity was the first and only civilised species on knowledge gleaned from the fossil record. However, a civilisation that existed 200 millions of years ago would not have left a significant trace.
Imagine if we had a nuclear war today and went extinct. In 50 million years our cities would have become thin layers of calcium carbonate, or iron ore, 1000s of feet below the surface, no other trace would exist on the earth.
So if a very ancient civilisation did exist is the past, it would have left at best a marker in orbit, in the solar system, or on the moon- nothing would be left on earth that was easily detectable.
If we were to target a search for prehistoric civilisations what should we look for?
1. Concentration of Iron (EG "red beds"!!!)
2.Concentration of uranium/other heavy metal.
3.fossil record- global coveage of a species across climate/environment.
4. manipulator physiology in the fossil record - think outside the box- tentacles/elephant trunk etc not just fingers.
NB- this will be edited a lot over time!