Evolutionary equivalents of human intelligence
I am a confirmed skeptic, a dyed-in-the-wool atheist and a firm believer in the scientific method. My understanding of evolutionary biology, however, is rudimentary at best, so please bear with me if I mangle a some concepts and terminology...
My understanding is that for every adaptation that arises to deal with a particular environmental challenge, we often see different organisms in similar environments coming up with similar, yet different, adaptations. So, for example, sight is a wonderful adaptation for survival and there are many different types of eyes throughout the animal kingdom that apparently evolved independently of each other. The same could be said of something like camouflage, whether it be the ability to change color or an adaptation to resemble another animal or object.
Assuming this is, in fact, a fairly common occurrence (i.e., that different species adapt in similar ways independently of one another), it makes me wonder about what is arguably the greatest adaptation of all -- human intelligence. The adaptation toward conscious thought, self-awareness, complex problem-solving, the ability to think about and plan for the future, etc., has allowed humans to basically adapt to any environmental challenge we may face.
Given that human-style intelligence seems to be such an amazingly useful adaptation, I have to wonder why we don't see any analogs to it with other species? In other words, why are we the only species to have developed it (or something similar)?
Again, I ask you to excuse my ignorance. I know that there are plenty of species that show some degree of what we would call intelligence, including dolphins, parrots, apes and even octopi. But none seem to exhibit anything really close to the type of intelligence that has allowed our species to spread out over the entire planet.
Am I just being human-centric? Do evolutionary biologists, in fact, see analogs to human intelligence in other species? And if not, are there any theories as to why we are so unique?