It depends on what intelligence is defined as, and good luck trying to nail that one down. You can't even get people to agree whether dogs or cats are smarter (although the right answer is obviously cats
). People might say that dogs are intelligent (or smarter than cats) because they take signals and commands and they interact with us on a social level; however, I would say that dogs exhibit these behaviors because they social creatures/pack hunters (while cats are solitary hunters). Of course, social-ness and our notion of intelligence are closely linked, if not exchangeable. In animal brains, the size of the frontal lobe (compared to body size) is typically proportionate to the size of the average social group that animal tends to live in. (By the way, given current human frontal lobe size, according to this ratio our brains are equipped to thrive in social groups of around 50.)
But if intelligence could be defined, I think that we wouldn't want to define it precisely as being a social animal, or a quality resultant of being a social animal, simply because there are so many more things to consider. If you try to evaluate the intelligence of an other animal on human terms of intelligence, you will misunderstand them. I think it's more about how smart they are in the context of their own world, their own niche. For example, cats are more cautious and stealthy than dogs, their movements are efficient and well-balanced, controlled (I think that for many animals much of their intelligence or intent or talent/skill is expressed through motion). It would be much more difficult to strike a cat with as much force as you could strike a dog (not that I've tested it) because cats twist/bend away from blows, maybe exhibiting a greater intuitive sense of physics than many animals. If you go away from home for a week, and leave your dog alone and leave a bunch of food out the dog will eat it all at once, while a cat would eat some and then leave it for later, and in general cats have a better chance of independent survival, for a number of reasons.. Cats will also interact with you socially, but not as often and not in a submissive sense, they are more unpredictable and mysterious (which would appear to distinguish them from more input/output types of creatures).
Maybe a vulture is the smartest animal in the world because they will be the last to run out food in the event of some sort of cataclysmic event. (obviously that would imply to scavengers in general, but vultures are emblematic.)
In any case, I am pretty sure that humans are the dumbest animals out there.

But if intelligence could be defined, I think that we wouldn't want to define it precisely as being a social animal, or a quality resultant of being a social animal, simply because there are so many more things to consider. If you try to evaluate the intelligence of an other animal on human terms of intelligence, you will misunderstand them. I think it's more about how smart they are in the context of their own world, their own niche. For example, cats are more cautious and stealthy than dogs, their movements are efficient and well-balanced, controlled (I think that for many animals much of their intelligence or intent or talent/skill is expressed through motion). It would be much more difficult to strike a cat with as much force as you could strike a dog (not that I've tested it) because cats twist/bend away from blows, maybe exhibiting a greater intuitive sense of physics than many animals. If you go away from home for a week, and leave your dog alone and leave a bunch of food out the dog will eat it all at once, while a cat would eat some and then leave it for later, and in general cats have a better chance of independent survival, for a number of reasons.. Cats will also interact with you socially, but not as often and not in a submissive sense, they are more unpredictable and mysterious (which would appear to distinguish them from more input/output types of creatures).
Maybe a vulture is the smartest animal in the world because they will be the last to run out food in the event of some sort of cataclysmic event. (obviously that would imply to scavengers in general, but vultures are emblematic.)
In any case, I am pretty sure that humans are the dumbest animals out there.