Answer:
I believe it would most likely be because of a drought, flood, and/or temperature changes. Climate change also affects the food supply, meaning they were nomads and just trying to find food.
Hope this helps! God bless!
With the melting Ice caps the Ocean around us is rising. Making the land around the U.S. shrink. Now if we are talking in the past the land became larger around the iceage because of the freezing water.
