"Intelligence" is a human defined term. That of a chimpanzee, for example, is much greater than that of a fish. And we humans say that ours is some level of magnitude beyond that of the chimpanzee. Given the billions of years that the universe has been in existence, I don't think that it's much of a stretch to believe that intelligence has evolved many orders of magnitude beyond that of the human being (which has only been around in our present form for a few hundred thousand).
I think that there is so much more to the universe, to reality, that is far beyond our ability to comprehend--not a lack of knowledge, but a lack of intelligence.