I think cats can be just as smart as dogs. Sure, they haven't rescued anybody from the snow, but have you seen size relations??!! I mean, St Bernard's are usually the "rescue" dogs, and a poor cat can't compare to that dog's size!
My cat happens to be rather smart, as it runs in the family. I mean, dogs have better scent receptors than cats and are much larger, as earlier said, but cats have potential too!
Even though I have said all of these things that dogs are larger, are better rescuers, cats are much better as an elderly companion. Dogs usually make much more noise than cats and sometimes whine all night. Cats can find their way home, as do dogs, and you let them out at night, but dogs are chained up!
I LIKE dogs, sure, and I like cats, but all I'm trying to say is that even though dogs learn tricks and all, cats have the potential to be smart anyway. If you're patient enough, you can teach an animal almost anything (besides playing piano, etc...).