zoo, natural history museum, and botanical garden located outside Tucson, Arizona, U.S., near the western entrance to Saguaro National Park. Founded in 1952, the museum houses indoor and outdoor displays of living animals and plants native to the Sonoran Desert, an arid region embracing parts of the U.S. states of Arizona and California and the Mexican states of Sonora and Baja California Norte. At the turn of the 21st century it housed 1,300 species of plants and many mammals, birds, reptiles, amphibians, fish, and arthropods. The museum engages in many research and conservation projects relating to desert ecology and particularly to the Sonoran Desert. Among its many exhibits are a walk-in aviary, a cactus garden, a pollination garden and hummingbird aviary, and a demonstration of animal life underground.