I sometimes quip that I'm a "third-generation atheist" - both my parents are atheists, and my maternal grandparents were both atheists too. (I don't know about my paternal grandparents; I never really knew them.)
But it occurs to me that somewhere deep in my ancestry, there must have been someone who was a first-generation theist - the first to be converted to a theistic religion. And, even further back, there must have been a first-generation animist. I'm pretty confident that the former of those two must have looked recognizably human, but I'm less sure about the latter. Might H. sapiens sapiens have arisen as already animist, as we arose as already tool-makers?
We don't know anything at all about Neanderthal or H. erectus spiritual or religious life, or if they even had any. We do know that at least some Neanderthal populations had ceremonial burials, but we don't know if this was done out of any concern for the spirit of the deceased or to manage grief in the living.