Intelligent life and the kardashev scale

What is considered intelligent life. If scientists find life on other planets how would they classify which are intelligent life and which are not? I mean human beings are considered intelligent life even though we rank as a Class 0 civilization on the...

Kardashev scale. I wonder if it is biased, but anyway what determines if something is intelligent life. What would it have to correspond to on the Kardashev scale. Were humans always considered intelligen life? If not when did humans evolve enough to be considered intelligent life? Please tell me how scientists classify intelligent life and when did humans become intelligent life?

whats the kardashev scale funmail me it seems like a very interesting topic

I am not sure about the precise definition but I do know that the ability to make and use tools is an indicator of intelligence.

If this is so that chimpanzees must also be intelligent life? Yet scientists only consider humans to be intelligent life. This seems contradictory.