The grizzly bear symbolizes the wildness of the Yellowstone region. Monitoring this population is a complex, long-term effort involving multiple state and federal agencies. Determining how many of these carnivores roam the landscape is not a simple census but a sophisticated scientific estimate. This figure indicates the species’ recovery and measures the success of decades of conservation work. Understanding the current population requires looking closely at the vast area they inhabit and the precise methods scientists use to track them.
The Current Population Estimate
The most recent population figure for grizzly bears in the Greater Yellowstone Ecosystem (GYE) is an estimated 1,030 individuals as of 2023. This figure is a statistical estimate derived from an advanced computer model, not a precise headcount. The Interagency Grizzly Bear Study Team (IGBST) uses a complex “integrated population model” that incorporates multiple data streams to generate the most robust estimate to date. This model significantly revised the previous number, which had hovered around 700 bears, by incorporating a wider array of biological data. The population in the core monitoring area has more than quadrupled since the early 1980s.
How Grizzlies Are Counted
Scientists with the IGBST rely on multiple metrics to feed their integrated population model. A traditional method monitors the number of unique female bears accompanied by “Cubs of the Year” (COY). These breeding females represent the reproductive heart of the population, and their documented numbers provide a minimum count that is then extrapolated. Biologists track these unique family groups from the ground and air to establish reproductive trends and survival rates.
The integrated population model combines this data with information from radio-collared bears and other population indicators. This approach incorporates survival rates for different age and sex classes, reproductive frequency, and mortality rates, including estimates for unreported human-caused deaths. By forcing these indicators to align mathematically, the model “self-reconciles” the data, producing a more accurate total population size.
Defining the Ecosystem Boundary
The population estimate applies to the Greater Yellowstone Ecosystem (GYE), a vast region much larger than Yellowstone National Park (YNP) alone. The GYE is one of the largest nearly intact temperate-zone ecosystems remaining, spanning approximately 22 million acres across parts of Wyoming, Montana, and Idaho. Yellowstone and Grand Teton National Parks are at its core, but the ecosystem also includes surrounding national forests and private lands.
This extensive, multi-state area provides the necessary space and diverse habitat for a viable, self-sustaining grizzly population. The bears’ occupied range has expanded threefold since 1990, now covering over 27,000 square miles. Because the bears roam far beyond the national parks, the population figure must account for the entire, interconnected ecosystem.
History of Recovery and Conservation Status
The current healthy population is a direct result of decades of intensive conservation following a period of near extinction. By 1975, only an estimated 130 grizzlies remained in the Greater Yellowstone area, a dramatic decline from the estimated 50,000 that once roamed the lower 48 states before European settlement. This crisis led to the species’ protection under the Endangered Species Act (ESA) in 1975, which ended the unrestricted killing of bears and initiated formal recovery efforts. The ESA listing spurred the formation of the IGBST and established minimum population and distribution goals that have since been met.
The successful recovery has resulted in a recurring legal debate over the species’ conservation status. The U.S. Fish and Wildlife Service has twice attempted to remove the GYE grizzly population from the threatened species list (in 2007 and 2017), arguing that the population met its recovery benchmarks. In both instances, federal courts vacated the delisting rule, reinstating the species’ threatened status under the ESA.
The legal back-and-forth centers on whether the GYE population qualifies as a “Distinct Population Segment” and if delisting would compromise the population’s long-term health. The current status means the bears remain under federal protection, which dictates management strategies for human-caused mortality and habitat protection. State agencies in Wyoming, Montana, and Idaho continue to petition for delisting, arguing that the population is recovered and should return to state management.