Dancing to me is like being married to the music. Some of it is cultural. A lot is cultural. We see it in ballet especially. If we could go back to prehistoric times, we would find them dancing. Just swaying our bodies to the music. As dancing advanced through time, it took several turns, but the main two that I can see, is dancing for social, and dancing as ceremonial. They could include celebrating births, birthdays, deaths. In tribal dances, there were ones that were medicinal, religious, such as in asking the Gods to end a famine, or to provide rain. Way before their language was perfected, they used dance to communicate.