The Aden Lava Flow Wilderness is characterized by basalt flows, volcanic craters, and coppice sand dunes. The lava flow includes pressure ridges, lava tubes, and steep-walled depressions of up to 100 feet wide. Grass and shrubs grow on the flow with many cacti and yucca. Vegetation consists of grasslands and desert shrubs such as mesquite and creosote. Vent tubes, and the many crevices found in the lava, provide cover and den sites for wildlife. Melanistic (dark) forms of mammals and reptiles occur on the black lava flows. including the rock pocket mouse and black-tailed rattlesnake. Bats are also numerous, making their homes in the cracks of this broken lava landscape.