Office of External Affairs
Mountain-Prairie Region


U.S. Fish and Wildlife Service
Mountain-Prairie Region
134 Union Boulevard
Lakewood, Colorado 80228

April 14, 2010


Contacts: Dan Blake: 307.772.2374 ext. 227;

                Pat Deibert: 307.772.2374 ext. 226;

                Leith Edgar: 303.236.4588;



Endangered Species Act Protection for the Wyoming Pocket Gopher is not warranted


The U.S. Fish and Wildlife Service announced today it has completed a status review of the Wyoming pocket gopher (Thomomys clusius) and has determined it does not warrant protection as a threatened or endangered species under the Endangered Species Act. The Service made this finding after a thorough review of all the available scientific and commercial information regarding the status of the Wyoming pocket gopher and potential impacts to the species.


The Wyoming pocket gopher is a small, light-colored mammal of the Geomyidae (pocket gopher) family, with a length of approximately 6.5 to 7.5 inches and a weight of 1.5 to 2.5 ounces. The species is characterized by powerful front limbs with long nails used for digging, small ears, small eyes, and fur-lined cheek pouches used to carry food. Pocket gophers are fossorial, living most of their lives in burrow systems and underground tunnels. The species’ tunnel systems provide protection from predators and extreme environmental conditions. The Wyoming pocket gopher is one of nine species currently assigned to the genus Thomomys.


Based on the life histories of other pocket gophers, Wyoming pocket gophers likely do not live more than two breeding seasons, reproduce the calendar year following birth, and have one litter with four to six young annually. The species’ diet is likely primarily the roots, stems, and leaves of forbs, with some consumption of grasses and shrubs.


Relatively little is known about the Wyoming pocket gopher. Assumptions about its distribution, ecology, and status are based on a few museum records, anecdotal reports from about 30 years ago and research conducted in 2008 and 2009.  It occupies an extremely small range, both historically and presently. The known distribution of the species is restricted to Sweetwater and Carbon Counties in Wyoming.


In 2008 and 2009, the Wyoming Natural Diversity Database, along with other groups, trapped pocket gophers, including 31 of the Wyoming species. Service scientists used these data in comparison to historic records to determine if the species’ known locations have changed over time. The Service determined that the Wyoming pocket gopher currently inhabits its known range in a pattern that approximates its historic distribution. In other words, we have no indication that the species’ range has been diminished.  


The Service analyzed potential factors that may affect the habitat or range of the Wyoming pocket gopher, including energy development, road construction and utilization, non-native species and climate change. None of the factors analyzed could be identified as potential threats to the species. 


Energy development in the range of the Wyoming pocket gopher includes oil, gas and wind. The life of major oil and gas development for the Wyoming pocket gopher’s range is estimated at between 10-50 years. Peak development of renewable energy is estimated as occurring in 2030, according to the U.S. Dept. of Energy. Clearly, the likelihood of energy development across the species’ range is high. However, potential disturbances due to energy development do not always adversely affect pocket gopher species. Rather, in some cases disturbances have benefitted some pocket gopher species. Therefore, the impact of energy development on Wyoming pocket gophers cannot be determined based on the best existing scientific evidence.


Service scientists also considered the effects of road construction and use on the Wyoming pocket gopher. Though the effects of roads on Wyoming pocket gopher populations are not known, limited anecdotal observations of individual gopher occupancy near roads does exist. Like gas development, road construction and use was judged as having neither a positive or negative effect on Wyoming pocket gopher populations.


Non-native species were also analyzed for their potential to impact Wyoming pocket gophers. Cheatgrass (Bromus tectorum) is chief among non-native species impacting the habitat of the Wyoming pocket gopher. Scientific evidence of how non-native species are impacting the Wyoming pocket gopher is not available. Consequently, non-native species were found to have no discernible effect on the Wyoming pocket gopher.


The Intergovernmental Panel on Climate Change (IPCC) concludes that human-caused global climate change is occurring and has published research that represents the best available science on the subject.   

Because most of the IPCC climate change models apply to large, general scales; Service scientists used models to try to predict how increasing temperatures would affect the Wyoming pocket gopher and its habitat. Analysis of the models did not determine how climate change would affect the Wyoming pocket gopher. 


Because of the limited distribution of Wyoming pocket gophers, the Service also analyzed small population size. Currently, we do not have sufficient information on population size, dispersal strategies or distribution that indicates other manmade or environmental factors would create a threat to the Wyoming pocket gopher. Further, the historic range and persistence of the species’ population size suggest the species occurs in normally low population densities.  The limited available data suggest that the overall distribution of the species has not changed since the 1970s.


Based on the current information available, the Service finds that the magnitude and imminence of threats do not indicate the Wyoming pocket gopher is in danger of extinction or likely to become endangered within the foreseeable future throughout all or a significant portion of its range.


In August 2007, the Biodiversity Conservation Alliance and Center for Native Ecosystems submitted a petition requesting the Service list the Wyoming pocket gopher within its known historic range and designate critical habitat. Once funding for listing became available in 2008 the Service addressed the petition. Then, in November 2008, the petitioners filed a complaint with the U.S. District Court for the District of Colorado alleging the Service failed to complete its 90-day finding. In February 2009, the Service published its 90-day finding, which indicated the petition presented enough evidence that listing of the Wyoming pocket gopher may be warranted. In June 2009, the Service agreed to complete the 12-month finding by April 10, 2010.


The Service also asks the public to continue to submit any new information that becomes available concerning the status of or impacts to the Wyoming pocket gopher. This information will help the Service monitor the status of the Wyoming pocket gopher. Please submit your comments to the U.S. Fish and Wildlife Service, Wyoming Ecological Services Field Office, 5353 Yellowstone Road, Cheyenne, WY 82009. The Service continues to encourage ongoing conservation efforts on behalf of the Wyoming pocket gopher.


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on our work and the people who make it happen, visit


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