Host David Yetman, Ph.D., is research social scientist at the Southwest Center of The University of Arizona in Tucson. He has worked as a university professor, camp manager, clock maker, construction worker, legal researcher, member of the Pima County (Arizona) Board of Supervisors and executive director of the Tucson Audubon Society. He received his doctorate in philosophy from The University of Arizona.

Dr. Yetman is also a nationally known author and accomplished photographer. His books include: "Where the Desert Meets the Sea: A Trader in the Land of the Seri Indians"; "Sonora: An Intimate Geography"; "Gentry's Río Mayo Plants, the Tropical Deciduous Forest and Environs of Northwest Mexico"; and "Scattered Round Stones: A Mayo Village in Sonora, Mexico." His most recent books are "Mayo Ethnobotany: Land, History, and Traditional Knowledge in Northwest Mexico," co-authored with ecologist Thomas R. Van Devender, and "Guarijíos of the Sierra Madre: Hidden people of northwest Mexico."

In the last decade, Yetman has carried out intensive studies of desert and thorn forest/dry tropical forest peoples in the Mexican states of Sonora and Sinaloa. Yetman focused his research on the locals' use of their lands and especially their plants. He has also worked to establish preserves for the great organ pipe cactus forests of southern Sonora. Yetman's current projects include studies of the great columnar cacti of North America, South America and the Caribbean, and how they have influenced and been influenced by cultures and a history and geography of the Opata people of northeastern Sonora, Mexico.

Yetman's background and interests are a perfect fit for the adventurous new direction of "The Desert Speaks." As the crew journeys to some of the driest places on Earth - from areas just south of Tucson to dangerously remote peaks in Argentina and Bolivia - his enthusiasm, abundant energy and expertise will no doubt be called upon frequently.