The difference between humans and the other animals seems to be purely mentation...

[Guest]

I think we are the product of an alien intervention , perhaps they do this on many planets . Start off with reptiles and let the experiment run a few million years then introduce the next group of animals and finally humanoids . Not really sure how these aliens travel vast distances to watch over their experiments but maybe its like star trek and they can dematerialize and reappear where they want .