I am convinced that we are more like our primate cousins, and indeed the rest of the kingdom of life, than we usually care to admit.
But if asked what I think the essential difference is between human beings and, say, chimpanzees ~ I'll say that it is only we human beings who pray.
Of course I could be wrong about that. Would we recognize the prayers of chimpanzees, orangutans, and gorillas? In the past we've often had a hard enough time hearing the prayers and seeing the humanity in others of our own species.