On our way to Wind Cave we had to stop at a Buffalo cross walk! We were lucky enough to be on the road when the local wild herd of buffalo decided the grass was greener on the other side of the road. Several cows and calves crossed, then a large bull. They stood in a group and munched for a while, then the bull walked back toward the road and watched another group of cows and calves who were skittish about crossing. He gave a bellow that sounded somewhat like a lion roar, and the dawdlers charged across, even with a parked car within 5 feet of where they were crossing. This area has a herd of about 800, that roams freely over 28,000 acres of parkland. We were lucky to have seen them.
The Wind Cave tour was interesting since there is only one known natural entrance and that is about two feet by three feet wide. The barometric pressure difference between the outside and the inside of the cave cause it to “breath”. Sometimes the air blows out and sometime in, depending on high and low pressure changes in the atmosphere at the cave entrance.
This cave is dry so it has no stalactites or stalagmites, but something called box work. The name refers to the formations appearance resembling post office boxes. They formed from gypsum seeping through cracks and turning into calcite after the water in the caves dissolved the limestone and the calcium in the gypsum. These formations were present when the caves were formed and will not ever change like the decorations in other types of caves. Wind Cave is the fourth longest cave system in the world, but the caves are like narrow low tunnels stacked on top of each other. The entire system is contained in an area of less than a square mile.