On some level hasn't time and language demonstrated on how different we are from animals. Those traits that you find similar in animals, eg. the elephants returning to the site of the dead, basic tool making, etc, never evolve past those developments. Why ?
The assumption might be that it takes time to develop, but those species never move beyond simplistic uses of language and tools despite their ancient ancestry.
Whatever your thoughts are on the evolution and biology of life, something is happening in the prefrontal cortex of humans that is fundamentally different.