I'm just throwing my opinion out there even if it sounds a little dumb.
What says which one is smart and which one is not? Just because Alakazam can Rival a god's Brain-Bandwidth does that mean he could forage like the Rattata? Or the Slowking -- Does it take more Intellect to be born with the ability to speak, or to Learn the hard way like Meowth?
I mean, I don't have much of a point, but what says one's the 'Smartest'. I think they're all smart in their own way -- Sure Slowking can speak, but Another can be taught a more impressive technique then he.
I'm about to be argued right out of this aren't I? XD