I know why humans cry. Because people get sad. Tears are a result of overwhelming emotion exiting the body. Tears are the soul expressing its feelings. Everyone has cried, and you can think of when and why, and it makes sense.
But think about it in a purely evolutionary manner. Think about crying in terms of biological reasoning. Why does it happen? No other species cries. We nurture our young, just like other species. We live in a society and around others of our own kind, just like other species. We prey on smaller animals for our food, just like other species. But we shed tears, and shedding tears is something other species don’t do. Sure, animals howl and whimper, but those are typically a result of pain. Humans cry frequently, and for more reasons. But what is the biological benefit of shedding tears? Why does shedding tears help? Why do tears leaving our eyes make us feel better? How did we evolve to shed tears?