If Nature Is Designed For Collaboration, Why Is It A Learned Skill For Humans?

There are hundreds of apple trees around my neighborhood. Almost each morning and afternoon deer from a close-by mountain venture from their grazing places to my front yard (and neighbors) to munch on the morning sweetness. As I ponder the cuteness of the deer, I'm struck by the apple tree. What a marvel of natural collaboration: grow apple, deer eat, deer poop, seed flourishes... Is it me, or does nature follow the rules of collaboration, always? It begs the question, what happened to our natural ability to collaborate?