"I wonder how things would have been if intelligence had evolved in a more solitary, non-tribal species, like the orangutan."

Today we would all still be highly intelligent tree-dwelling fruit-eating misanthropes.

Human beings are social animals, our strength lies in our ability to function in groups, even if we pay a high price for this. In fact, I believe our intelligence is a result of our social proclivities,not the other way around. It doesn't really make any sense to speak of a hypothetical Homo solo. Our capacity to live in groups provided the environment that forced usto evolve more intelligence.

Humans have never had the physical equipment to allow them to compete effectively against more efficient food-gatherers or predators, all the intelligence in the world won't help you if you are physically overwhelmed, sheer brain power by itself cannot compete in the short term with sheer strength.

Instead we have always clustered into the largest groups our environment/technology could support, because in this way we could muster the group strength through cooperation and specialization to make up for the fact we were individually slower, weaker and more fragile than our competition. High intelligence probably could not have evolved in a solitary species, and communication, a big component of intelligence, would not have evolved in a lonely hunter at all.

It may stroke our egos, or our prejudices, to think in simplistic terms of strong, noble, individualistic solitary hunters as opposed to weak, docile collectivist herd herbivores, or even to seek in that dichotomy some justification for our desires and fantasies. But I think that is more an artifact of our desires and the way we look at the universe than any evolutionary imperative. In truth, the tribe is a rich, complex environment that favors, indeed, forces, intellectual development, and breeds leaders as well as followers. It allows us to exploit the skills, talents and memories of the old and the weak so they can still contribute to the group even when they are past their physical prime. I may no longer be young enough to hunt, fight, or mate, but I can still teach the youngsters how to do all three more effectively.

Don't sell collectivism short, its who we are. The rugged individualist can only afford the luxury of being that way because he depends on the others in his tribe to actually do the work. Without him, the tribe will still survive, which is why young powerful males are always expendable. But by himself, alone, he's just another naked ape cowering in fear on the savanna.