I once had a cat that was freakish smart (on a par with an average dog). This first became evident when one day I was hiding behind a box and using a 'fishing line' to play with the feral kittens. All but one chased the string in the usual way. The freak looked at the string, looked UP the string, then jumped over the box to grab my hand. (Which is exactly what average puppies will do.) This cat later became a house pet... which gave me opportunity to watch him with mirrors. The other cats thought something they saw in the mirror was IN the mirror. But the freak would immediately look over his shoulder at whatever had just appeared in the mirror. He had all manner of freak-thinking behaviors I've never seen in another cat. (Incidentally, he was a hermaphrodite -- born female, developed male genitals at about 3 months. And was the product of 4 generations of inbreeding down from one female, which I only knew because the feral colony there was small and isolated.)
More typical, tho, were my feral barn kittens... I'd bang the dish on the concrete to call them for breakfast. And if after a couple days I then held the dish out of their reach, rather than looking up like "Hey, where's my dish?" like a puppy will, the kittens tried to eat the concrete floor. I wish I had video; it was hysterical. And a good demonstration of how dumb most cats really are -- tho they *condition* so rapidly that they appear 'smart'.
[I'm a pro dog trainer, but I usually also have several cats.]