I guess its all in how "intelligence" is defined. Ask a goldfish to do your taxes.. he can't, we call him dumb. Ask a velociraptor to hunt in a pack, and you'll end up dinner. I would say that the human race is the least intelligent dominant species to inherit the planet.

Most definitely!!!!

It was doing so well until humans killed it.

The article I read about this said that the most interesting angle of asking the question is to find out what kinds of long term effects civilization has on the geologic strata. If they find a method to test for civilizations, they can use it on other planets as well. Such as a layer that is high in CO2 or carbon from burning fossil fuels. In that way, we can someday find out if there were others. Time is so vast that even if alien civilizations existed, there is a good chance that they miss each other in space-time.

Well considering that our civilization would be reclaimed by nature in about a thousand years it's possible that another one could have existed.

I don't think it exists now unless you have a pretty low bar for intelligence. ?

Read this story in a couple of different news and science sites. Millions of years, time enough to erase any evidence so there is always a possibility however slim.

Was There a Civilization On Earth Before Humans? - The Atlantic

Where it is a possibility, it is highly unlikely based on evidence so far.

If intelligent life existed on this planet at all, it would have had to existed eons ago as none exist now.