One of the world's longest and most complex caves and 28,295 acres of mixed-grass prairie, ponderosa pine forest, and associated wildlife are the main features of this park. The cave is well known for its outstanding display of boxwork, an unusual cave formation composed of thin calcite fins resembling honeycombs. The park's mixed-grass prairie is one of the few remaining and is home to native wildlife such as bison, elk, pronghorn, mule deer, coyotes, and prairie dogs. Leashed pets are allowed on Elk Mountain Nature Trail and Prairie Valley Trail, as well as in developed areas, such as picnic areas, parking lots, and along gravel and paved roads. Pets are not allowed in the buildings or on other park trails. Leashes must be no longer than six feet.