There are two different types of grasslands; tall-grass, which are humid and very wet, and short-grass, which are dry, with hotter summers and colder winters than the tall-grass prairie. The settlers found both on their journey west. When they crossed the Mississippi River they came into some very tall grass, some as high as 11 feet. Here it rained quite often and it was very humid. As they traveled further west and approached the Rocky Mountains, the grass became shorter. There was less rain in the summer and the winters got colder. These were the short-grass prairies.