Wyoming wildlife officials are sounding the alarm as a harsh summer of record heat and drought has taken a toll on the state’s iconic pronghorn. In the Green River Basin, 14% of the GPS‑collared animals in the Sublette Herd have died over a six‑week period, primarily from malnutrition.
Deaths linked to lack of food
Wildlife management coordinator Brandon Scurlock of the Wyoming Game and Fish Department’s Pinedale Region received two mortality alerts in early August. The first was for an old female, PH143, found dead along the receded shoreline of Big Sandy Reservoir. A post‑mortem showed her bone marrow was red and gelatinous, a clear sign of severe nutritional stress.
Within days, a second collar signaled another death in the Dry Piney Creek drainage. By September 13, a total of seven collared pronghorn had perished. The animals that died were all non‑migratory individuals that remained on the winter range year‑round, a strategy that proved fatal this summer.
Vegetation failure in low‑elevation areas
Biologists attribute the deaths to the near‑complete loss of winter browse in low‑elevation habitats. Survey work by Game and Fish terrestrial habitat biologist Troy Fieseler in the Prospect Mountains showed up to 90% of bitterbrush shrubs dead in some spots. Surviving plants produced only a quarter‑inch of new growth – roughly 10% of normal rates – and began defoliating weeks ago.
“He measured basically zero growth on bitterbrush leaders,” Scurlock reported, underscoring how the parched vegetation left little sustenance for the pronghorn that could not migrate to greener pastures.
Broader impacts of the drought
The drought’s effects extend beyond pronghorn. While wildfires have burned more than 63,200 acres this year, that figure is a fraction of the 810,000 acres scorched in 2024 and 250,000 acres in 2025. The dry conditions have also spurred unprecedented black‑bear conflicts and prompted emergency orders for livestock owners.
Despite these challenges, Deputy Chief of Wildlife Martin Hicks noted that disease outbreaks have been limited. Only a single case of epizootic hemorrhagic disease has been confirmed, far fewer than expected given the drought conditions.
Signs of resilience
There are encouraging signs amid the hardship. Biologists reported a fawn‑to‑doe ratio of more than 60 fawns per 100 does, surpassing the five‑year average. Additionally, migratory mule deer in the Wyoming Range appear plump with ample antler growth, though officials warn that winter forage will be scarce.
“Tons of body fat on them, but I think they’re going to need it this winter,” Scurlock said, emphasizing the need for continued monitoring and habitat management.
Looking ahead
State wildlife officials plan to continue tracking the herd and assessing vegetation recovery as the winter approaches. The goal is to ensure that enough healthy browse is available to support both migratory and resident pronghorn, preserving a species that is a hallmark of Wyoming’s natural heritage.
For more information on wildlife health updates and ways the public can support habitat restoration, visit the Wyoming Game and Fish Department website.
Original reporting: Buckrail (Jackson WY) — read the source article.
