While our closest animal relatives have been swinging from the trees, humans have built a world that is vastly more complex. What are the defining features that have allowed us to do this? Are we special, and separate from all other animals, or are we just an especially successful mammal?

While our closest animal relatives have been swinging from the trees, humans have built a world that is vastly more complex. What are the defining features that have allowed us to do this? Are we special, and separate from all other animals, or are we just an especially successful mammal?