I wouldn't go so far as to say that, because dogs are also more intelligent than some people would like to think. What most people don't take into account is that intelligence is a tool, and humans, dogs, and horses use that tool in different ways to attain our ends.
Too many people draw the wrong lesson from the case of "Clever Hans" Clever Hans - Wikipedia, the free encyclopedia The horse was supposed to be able to count, but when researchers discovered that he had instead figured out how to use subtle body language cues to deduce the answer that the questioner wanted, they just said "Stupid horse can't really do math", instead of recognizing that he was intelligent enough to perform a far more sophisticated task - one which I have to admit I wouldn't have a hope of do myself, despite my "superior" human intelligence, and math degree
Hans is a very interesting case. I don't know that I believe the "researchers" results. Unfortunately, it wasn't filmed and there was no further "testing". My daughter knew how to read before she was two. She was also very shy. She couldn't say her abc's in front of a crowd at age 4 w/o me. This proved? I kind of look at Hans as, "what if Jesus came to earth?".