There are a lot of theories about what separates humans from animals. Some say it is our use of tools and the civilization that we have built. Others disagree. When you look at all the negatives we have created in our society, it is hard to argue that our civilization is a positive differential.
Personally, I think Frank Herbert got it right when he wrote Dune. He posits that what makes us human is the ability to overcome are baser instincts, letting our mind control our actions. He conceived of the Gom Jabbar test which I think clearly illustrates the difference.