I don't necessarily agree that humans are at one end of the "intelligence" spectrum. Intelligence has been defined as "an ability to adapt oneself to a changing environment" and I'm not sure that I see a lot of that in many of the humans I know! I think we flatter ourselves because we have mastered a complex system of sounds that we call language and "dumb" animals haven't. That doesn't stop lots of communication between my dog and me. If he wants something, he's very good at letting me know that and when I get out of my chair to see what it is, he will point to the place where the object of his desire resides. If it's a piece of liver cake, he stands by the fridge. A chew, he points at the shelf. If his water bowl is empty, he points at that. If he wants a game with his ball, he comes and plonks the slimy, muddy artefact straight in the middle of my keyboard.
I expect he thinks I'm very dim because I can't get immediately from his thoughts what it is.