The plains culture tribes were the tribes that were located in the Great Plains of North-America, that form the states of Montana, North Dakota, South Dakota, Wyoming , Nebraska, Kansas, Colorado, Oklahoma, Texas, and New Mexico, they are the most typical and known tribes of north america and were nomads, their diet consisted on buffalo and crops they could gather. As they were nomads they were the most affected by the arrival of the colonizer because their way of life was uncompatible with the European way and all efforst to colonize them were unsuccessfull.
The Mexican army attacked them. The main cause of the war was the westward expansion of the United States. All through the 19th century Americans believed it was their right to expand westward. At the time they believed they could conquer the people already living on the land and take it for the United States.
