When people go hiking or camping in back country or wilderness areas, they almost always impact the natural environment in some way. When people use the back country, they sometimes use pack animals to make their trip easier. While much trampling occurs on trails, for pack animals, it can also occur where the animals are grazing. The scientists in this article studied what happens to vegetation that is being trampled by people, horses, and llamas. Note: In earlier Natural Inquirer articles like Topics: Recreation, Wilderness, Back Country, Erosion, Hiking, Horse, Llamas, Pack animals.