Well, I think that animals and us (animals too) are both intelligent and rational, we just evolved, back in time we were "dumb" as we think animals are but who thinks this way is wrong, you don't see animals throwing themselves from edges, when a dog goes to a precipice they don't jump to death, they have the ability to rationalize situations, dogs can cross streets, help blind humans to walk through cities and even find cancer presence only by smell, and many other things that we can't. In fact, what I think that differs us from them is the dexterity achieved by humankind, the know-how acquired by us is on another level, we were able to think, to question and to answer that questions, what really differs us is our philosophy and science, our mind and brain evolved too much and got the capacity of creation.