This subject is always worth philosophical discussion. What exactly separates humans from the rest of the planet, both now and in the past?
At one time, I thought the easy answer was fire. Only humans know how to manipulate fire. And, when it came to separating Homo Sapiens Sapiens From Homo Erectus or Homo Sapiens Neanderthalensis, it was how HSS used fire more creatively than the others. In other words, HSS engineered with fire, while the others maybe figured out how to cook with it, but that's about it.
All that said. I find that one other factor, perhaps a skill that is even bigger than fire is language. To be human is to master language. Having language is a huge advantage. It's perhaps the biggest advantage HSS had over anyone out there. Language makes us human? Maybe.
A third biggie is cognitive thought; specifically the ability to think ahead. Understanding cause and effect was paramount to our survival as a species back when we were both slower and weaker than our rivals. How do you beat a faster, stronger thinking upright primate? You out-think him by being more clever and cunning than it can be. That's how.
So, is it our ability to form complex thoughts; the capability to develop strategies by manipulating our environment to more closely suit idealized concepts that makes us human? Maybe it's all three.
A better question is; why do we have to be set apart from other Earth species?
My answer to your question though, is that nothing sets us apart from other animals. Nothing at all really, sure we have some awesome attributes but so do other animals. Birds can fly and not only fly but do it at an early age. If humans could fly at an early age, we would have gone extinct a long time ago. And that's even accounting for the evolutionary changes necessary to fly.