A creature with opposable thumbs or tentacles, since those work equally, just about, for maniupation (if they’re designed well enough) or any other limb that would end in some sort of adhesive from which it could pick stuff up. I think some flies have it on their front limbs or something, but I really don’t know. Just to throw out their are advanced manipulators besides opposable digits.
Oh, at the cat brain thing is a load of shit. They have a bigger cerebrum-to-cerebellum ratio than a lot of animals, but there is a WHOLE lot more important than that, when it comes to brains. Surface area, for example, I’m pretty sure cats are way behind, there.
I’d say overall, it depends on how things went down, but, I’m pretty sure robots would inherit the earth far, far in the future, after the Cataclysm kills most humans, their population will slowly dwindle due to a low survivability of infants and children, until the reproduciton rate is lower than the death rate with no sign of increasing. That’s when the robots truly win.
