Current Bighorn Sheep Research

Bighorns, like this lamb, are found from the Rims all the way to the Colorado River.

NPS Robb Hannawacker

 

Desert bighorn sheep that live within the Park are important not only for the Grand Canyon, but for other species as well. Bighorn sheep have a major impact on plant communities inside the canyon, and serve as a major food source for mountain lions, golden eagles, and the endangered California condor. The population of bighorn in the Grand Canyon is the only non-re-introduced population, making them important for bighorn conservation efforts across the southwest. Despite the regional importance, until recently little was known about in bighorn in the Grand Canyon. Current research is aimed at developing a monitoring program to understand the distribution, demographics, and genetic variation of bighorns in the Canyon, and to understand how they are impacted by diseases.

The remote landscape of the Grand Canyon makes studying these animals a challenge, but recent developments have allowed biologists to overcome these difficulties. A major development is the ability to obtain bighorn DNA from their feces, so that researchers can identify individual animals without ever seeing them. A second development is improved capture techniques, meaning that researchers can more efficiently capture and study bighorn inside the Grand Canyon with the use of GPS collars to monitor the movements of collared bighorns. These developments in technology and methods are contributing to the first comprehensive study of bighorn in the Grand Canyon.

A primary goal of the current research is mapping the distribution and seasonal movements of bighorn within the Grand Canyon. Initial research shows that large areas of the Canyon are unoccupied by bighorn. It is unknown if these areas are permanently unoccupied, or if they are seasonally occupied as bighorn move throughout the year. If these areas are permanently unoccupied, they may represent barriers that bighorn do not travel through, limiting gene flow between herds. Researchers are extracting DNA from bighorn feces, monitoring movement with GPS collars, and conducting visual surveys to better understand how bighorn occupy the unique and diverse Grand Canyon landscape.

Another major goal is to better understand how disease impacts desert bighorn sheep. Bighorn are closely related to domesticated sheep and goats, and are vulnerable to many of the same diseases. Several bighorn captured in the Canyon have been infected with bacteria normally found in livestock. These bacteria have been implicated in causing pneumonia-related mortalities in bighorn populations throughout the west, but population level impacts are currently unknown in the Grand Canyon.

By understanding these threats and the health of current bighorn populations, park biologists can create wildlife conservation policies that ensure that desert bighorn sheep will continue to be a part of Grand Canyon National Park.