If you think animals are dumb, you should watch this 
, which is about a tiger enlisting the help of a batallion of soldiers to rescue its cubs. Unfortunately the narrator is German, so not everyone will be able to follow it easily, but perhaps the YouTube subtitling feature will help you....
I saw such intelligence earlier in our first dog: it was playing with its ball, and the ball rolled under the couch. He looked at it, saw it was too far back to reach from the front, so it ran around the couch, nudged the ball from behind, and then ran around again to catch it. On another occasion I lifted a tile in the backyard, accidentally unveiling an ant nursery. Immediately, the entire army of ants began to move all eggs to lower corridors, because they needed to be in the dark!