The Chiricahua Mountains of southeastern Arizona lie in the Basin and Range Geological Province of North America, and rise to an elevation of nearly 10,000 feet. Ecologist C. Hart Merriam devised the life-zones system to help understand the relations between distribution of climate and organisms in North America. Each zone is climatically distinct and provides environmental conditions suitable for its own suite of plants and animals. The high diversity of flora and fauna within such a restricted geographical area is the result of climatic changes associated with elevational changes on the slopes of the Chiricahuas, and the impact of climatic history on evolution of the plants and animals in this biogeographical region. Field research always involves hazards, and this area with its teeming biodiversity is particularly dangerous.
All scientists working in the area are well informed about rattlesnake bites.
There are protocols for the first aid management and air evacuation of venomous snakebite victims in the Chiricahua National Park. There is, however, another potential health hazard. Twice during the 20th century prior to the 1990s, healthy, young Navajo members of the local tribe inexplicably died. In 1993, researchers tracking rodents in the area noticed the population of mice had increased ten-fold. Interestingly, the pinion nut trees were flourishing that year, as a result of melting snow and heavy rains.