For perhaps 30,000 years grizzly bears ranged throughout the mountains and riparian areas of what would eventually become the southwestern United States. But in a remarkably short 50-year period between 1860 and 1910 Anglo-Americans killed roughly 90% of the grizzly bears in 90% of the places they once lived. Most of the remaining grizzlies had been killed by the 1930s.
This report provides a detailed account of natural history, relations with humans, and current and future prospects for grizzly bears of the Southwest, emphasizing the millennia prior to ascendance of Anglo-Americans. The report’s narrative is essentially chronological, starting with deep history spanning the late Pleistocene up through arrival of European colonists (Section 3.1); the period of Spanish and Mexican dominance (Section 3.2); and then the period of terminal grizzly bear extirpations that began with the political and military dominance of
Anglo-Americans (Section 3.3). Section 4 examines current environmental conditions and related prospects for restoring grizzly bears to the Southwest. Section 5 completes the chronological arc by forecasting some of what
the future might hold, with implications for both grizzly bears and humans.
The background provided in Section 2 offers a synopsis of grizzly bear natural history as well as a summary of foods and habitats that were likely important to grizzlies. Throughout the Holocene there was a remarkable concentration of diverse high-quality bear foods in highlands of the Southwest, notably in an arc from the San Francisco Peaks of Arizona southeast along the Coconino Plateau and Mogollon Rim to a terminus in the White, Mogollon, and Black Range Mountains in New Mexico. Additional high-quality habitat existed in the Sacramento, San Juan, Jemez, and Sangre de Cristo Mountains of New Mexico and adjacent Colorado.
Grizzlies in the Southwest survived remarkable extremes of climate and habitats for perhaps as long as 100,000 years. They also survived substantial variation in human-propagated impacts that culminated in the Crisis of 875-1425 C.E.—a period typified by episodic drought and the highest human population densities prior to recent times. In contrast to relatively benevolent attitudes among indigenous populations, there is little doubt that the terminal toll taken on grizzly bears by Anglo-Americans after 1850 C.E was driven largely by a uniquely lethal
combination of intolerance and ecological dynamics entrained by the eradication or diminishment of native foods and the substitution of human foods, notably livestock, that catalyzed conflict.
More positively, the analysis presented here of current habitat productivity, fragmentation, and remoteness—as well as regulations, laws, and human attitudes—reveals ample potential for restoration of grizzlies to the Southwest, including three candidate Restoration Area Complexes: the Mogollon, San Juan, and Sangre de Cristo, capable of supporting around 620, 425, and 280 grizzlies each. Major foreseeable challenges for those wishing to restore grizzly bears to these areas include sanitation of human facilities, management of livestock depredation, education of big game hunters, coordination of management, and fostering of accommodation among rural residents. Climate change promises to compound all of these challenges, although offset to an uncertain extent by prospective increases in human tolerance.
But the evolutionary history of grizzly bears also provides grounds for optimism about prospective restoration. Grizzly bears have survived enormous environmental variation spanning hundreds of thousands of years, including many millennia in the Southwest. Grizzlies survived not only the inhospitable deeps of the Ice Ages in Asia and Beringia, but also the heat and drought of the Altithermal on this continent. It was only highly-lethal Anglo-Americans that drove them to extinction in the Southwest, which is why human attitudes—more than anything else—will likely determine prospects for restoring grizzly bears.