Why would they need to be humanoids?...
Why couldn't they be the size of an ant, with brain power that far exceeds ours?
Think about recent advances with technology.... we are always trying to make things do more,
in smaller packages.
For example...single computers used to take up entire warehouses, now, in just a matter of 50 years or so, we have got them down to the size of an eraser head... that are like millions of times more powerful than the ones that used to take up entire rooms.
So if you were to imagine that another species has already gone through this process for even... ten thousand years or so, what's to say they wouldn't wind up making themselves smaller??
If humans were the size of ants, a lot more of them could fit on the planet & it's resources would last much longer.
For all we know, we could already be sharing this planet with hundreds of species whos intelligence is far past ours... they could just be smart enough to stay off our radar in that way.
