Cynomys parvidens

Cynomys parvidens has been regarded as a subspecies of Cynomys leucurus by some authors. Thorington and Hoffmann (in Wilson and Reeder 2005) recognized the two taxa as distinct species.

This species has a limited range in southwestern Utah. Abundance decreased by approximately 90% in the last century and range extent decreased by approximately 50%. While the population rebounded in an exceptional manner through 2016, it declined from 2016-2020. An average of 52% of the population occurs on private land and protections for this species have been largely inadequate. It is threatened by disease,

This species is restricted to southwestern Utah in Beaver, Garfield, Iron, Kane, Millard, Piute, Sanpete, Sevier, Washington, and Wayne Counties (USFWS 2012, USFWS 2021, UDWR 2023). Using extant records from Utah Natural Heritage Program, range extent is estimated to be 22,888 km² (RARECAT 2025).

The historical range, prior to eradication programs that began in the 1920s, reportedly extended from Pine and Buckskin valleys in Beaver and Iron counties (perhaps west to Modena in Iron County), north to at least Salina Canyon and near Gunnison in Sevier County (possibly to Nephi), south to Bryce Canyon National Park, and east to the foothills of the Aquarius Plateau (Collier 1974, Pizzimenti and Collier 1975, McDonald 1997). The species is scarce or absent in the Aquarius Plateau, Fremont and Paria valleys, and Salina Canyon (Collier 1974, Pizzimenti and Collier 1975).

Distribution has expanded with Utah prairie dogs currently found in 391 occupied colonies throughout portions of 426 sections across the species’ range in 2022 (UDWR 2022). Applying a 5 km separation distance to extant records from Utah Natural Heritage Program (UNHP) (2025), 26 occurrences are estimated (RARECAT 2025).

This species is primarily threatened by persecution by private landowners, habitat loss, and plague. For the last century, this species has been deliberately killed by private landowners by means of poisoning and shooting, and that threat continues on private lands (Pizzimenti and Collier 1975, USFWS 2012, USFWS 2021). Habitat loss continues in the form of residential and commercial development, and conversion to agriculture (USFWS 2012, USFWS 2021). Habitat loss due to development is particularly important in Iron County, where 70% of the population of this species occurs, because population growth is expected to continue at 2.7% annually through 2060 (USFWS 2012). Overgrazing, invasive woody plant encroachment, and drought have both contributed to habitat degradation and are expected to continue (USFWS 2012, USFWS 2021). Plague, caused by a bacterium (Yersinia pestis) not native to North America and spread by fleas, is prevalent throughout the range and can cause high mortality rates (USFWS 2012). Unfortunately, the sylvatic plague vaccine has proven ineffective (USFWS 2021). However, flea control efforts at prairie dog colonies have increased survival rates (USFWS 2021). Vehicle mortality due to recreational off-road vehicle use and the maintenance of oil and gas energy infrastructure also present a threat to this species (USFWS, 2012, USFWS 2021).