That makes me wonder why we are the "intelligent" being in this world. Somehow we master technology and filosophy. We think, we wonder, we move the blocks.
Why are we the only "intelligent" being? Because intelligence is actually a very risky trait. The human brain is extremely power hungry, and consumes about one third of all your energy expenditure. An animal with a high brain mass to body mass ratio is required to consume more calories than a less brainy counterpart of similar size. So brain mass/intelligence can easily be selected against as opposed to being favored by natural selection.
As to why we became so much more intelligent than we actually need to be? Well, there is two main theories and they're both likely true.
First, adapting for adaptability. Most creatures adapt to specific and narrow range of environments in order to exploit those environments to their maximum potential. Our ancestors happened to need the the ability to adapt to new environments quickly... This required greater intelligence.
Secondly, being smart was selected for sixually. Think of intelligence as the human equivalent to the peacock's tail. It's way more extravagant than it needs to be. Even today most people list intelligence as a very important trait when choosing a spouse.