Borderlands

The region that spans the border of Arizona and Sonora is one of the largest, most diverse, and

intact arid landscapes in North America. The region’s life giving waters – the Gulf of California; the lower Colorado River; and the Colorado’s delta and major cross-border tributaries – are distinct and ecologically important counterpoints to the Sonoran Desert that surrounds them. Together, the arid lands and sustaining waterways of the borderlands form a system that is home to a myriad of unique plants, animals, people, and habitats.

The borderlands region lies firmly within the embrace of the Sonoran Desert, which is one of North America’s four major desert systems. North America’s deserts include the Great Basin, Mohave, Chihuahua, and Sonoran. Strikingly, although all four deserts are arid landscapes, they are distinctly different as the result of varying temperature and precipitation patterns.

As surprising as it may sound, the Sonoran Desert is lush in comparison to the world’s other deserts. The diversity of plant and animal life in the Sonoran Desert is a result of its subtropical location, geologic history, and bi-seasonal rainfall pattern. From December to March moisture carried from the Pacific Ocean falls as gentle rain throughout the Sonoran Desert. The region’s famous summer monsoon season runs from early July to mid-September, when wet tropical air and intense heat can result in violent, localized thunderstorms.

Though rain falls from the sky above the desert during two seasons of the year, average rainfall in the borderlands region ranges between 0 and 12 inches per year (0 to 40 cm/yr). The region receives the lowest amount of precipitation in North America. By comparison, the eastern coast of the United States gets about 40 inches of moisture per year (100 cm/yr).

Natural Features, Parks, and Monuments

The Arizona-Sonora borderlands contains a large concentration of protected areas that are located on both sides of the US-Mexico border, several of which are featured here:

Cabeza Prieta National Wildlife Refuge (click to learn more)

Cabeza Prieta National Wildlife Refuge was created in 1939 for the conservation of natural wildlife resources, including the endangered Sonoran pronghorn and lesser long-nosed bats, desert bighorns, lizards, rattlesnakes, and desert tortoises. The refuge encompasses over 860,000 acres of some of the most pristine tracts of Sonoran Desert remaining, making it the third largest refuge in the nation. The 1990 Arizona Wilderness Act designated over 90 percent of the refuge wilderness.

Cabeza Prieta, Spanish for “dark head,” refers to a lava-topped, granite peak in a remote mountain range in the western corner of the refuge. This rugged landscape is home to as many as 391 plant species and more than 300 species of wildlife. Visitors to Cabeza Prieta can enjoy plentiful hiking, photography, wildlife observation, and primitive camping opportunities. Visitors, however, are asked to avoid lingering near water holes, as wildlife depend on them for survival.

Organ Pipe Cactus National Monument (click to learn more)

Organ Pipe Cactus National Monument was established by Presidential Proclamation by Franklin Roosevelt on April 23, 1937, to protect the rare Organ Pipe Cactus and 26 other cacti species. The uniqueness and importance of this landscape is attested to by the rarity of the Organ Pipe Cactus itself, and the even more rare Senita Cactus, both of which are found nowhere else in the US. Encompassing approximately 330,000 acres of pristine Sonoran Desert, the Monument was established as a Biosphere Reserve in 1976.Organ Pipe Cactus National Monument is home to an extraordinary range of animals that have adapted themselves to the region’s extreme temperatures, intense sunlight, and infrequent rainfall. Six varieties of rattlesnakes, as well as Gila Monsters and scorpions, can be found at Organ Pipe. Other residents include the roadrunner, western diamondback rattlesnake, red-tailed hawk, coyote, cactus wren, javelina, desert tortoise, Gila monster, Gila woodpecker and white-winged dove.

The People

The ecological diversity of the Sonoran Desert is mirrored in its human inhabitants. Stretching from northwestern Mexico into the southwestern United States, the 

region is shared by Hispanic, Anglo, and Native American peoples. Historically, humans have inhabited this part of the Sonoran Desert for thousands of years. Ancestral inhabitants include the Hohokam, Patayan, Pinacatenos, and Arcnenos. The later two are clans of the Tohono (desert) and Hia-Ced (sand) O’odham, once known as the Pipage.

Contemporary borderlands residents live mostly in the cities, towns, and villages of southwestern Arizona, the Tohono O’odham Indian Reservation, and northwestern Sonora, Mexico.

To learn more about the Tohono O’odham click here.

Other Resources

We invite you to investigate the wide range of electronic resources, books, and videos that are available about the Sonoran Desert and her people. Some of our favorites include:

The Desert Smells Like Rain: A Naturalist in Papago Indian Country. 1987. Gary Paul Nabhan. North Point Press.
Ethnobiologist Gary Nabhan takes the reader on a series of journeys with the contemporary Papago Indians, the Tohono O’odham. Through a series of tales, Nabhan helps the reader understand these “Desert People” and their environment.

Gathering the Desert. 1985. Gary Paul Nabhan. University of Arizona Press.
This very readable book offers a compelling glance at the peoples of the Sonoran Desert through their traditional use of the desert’s plants for food and medicine. The book breathes life into learning about the plant life and peoples of the Sonoran Desert.

	Arizona Office of Tourism (click to learn more)
	DesertUSA (click to learn more)
	Great Outdoor Recreation Pages (click to learn more)
	International Sonoran Desert Alliance (click to learn more)

La Ruta de Sonora • Phone: 1.800.806.0766 • Email: [email protected]