One of them is smart enough to open doors, drawers, cupboards and find his way to the tops of our cabinets above the refrigerator.

The other one, however, is a complete twit. Total moron, terribly paranoid and dumb as a post. He has twouble finding his way out of a paper bag he's gotten himself into.
Interesting ... You don't assign a gender to the smart one ... but the dumb one is definitely male.

Possible Freudian slip, Tourguide?

Perhaps the 'dumb' one has learned to let the 'smart one' do all the work. Topping from the bottom, so to speak