The Sierra Nevada red fox is a subspecies of North American red fox that is considered native to the Oregon Cascades and the Sierra Nevada. It is a species that was listed as endangered by the US Fish and Wildlife Service in August 2021, thanks to a legal battle taken up - and won - by the Centre for Biological Diversity.
Sierra Nevada Red Foxes are generally smaller than other native fox species, weighing about 3 to 4kg and with a population size that is currently estimated to be between 10 to 50 adults.
They have similar characteristics to other red fox sub-species in North America, including the Cascade red fox and the Rocky Mountain red fox. They are also distinct from their European cousins in their fuller coats and longer guard hairs, their larger, well furred feet, and a predictable frequency of colour variations.
How did the red fox become an endangered species?
The introduction and expansion of the fur farming industry by European settlers, led to confusion that saw the North American red fox incorrectly labelled as non-native. Leaving them unsupported and hunted as an invasive species.
The North America red fox is native to Canada and North America and is well documented in the rich cultural heritage of the native North American Indians, being originally classified as the species vulpes fulva. This was changed to vulpes vulpes in 1959, based on anecdotal evidence. As a result, the red fox has been viewed as an invasive European import until recently, when scientists revisited the history of the North American red fox using modern genetic technology.
It appears that a combination of human activity, the misclassification of this species and expansion due to climate change, may have contributed to the diminished populations seen today.
There are 9 sub-species of North American red fox that are formally recognized; of the 9 sub-species of North American red fox recognized, several species are considered vulnerable by experts in the field, but it is only the Sierra Nevada red fox that has been listed for endangered species status to date.
Other red fox species of concern include:
the Cascades red fox (Vulpes vulpes cascadensis)
the Rocky Mountain red fox (Vulpes vulpes macroura)
How can you help these rare foxes?
Various organisations are raising awareness of the plight of this species in peril. You can support these foxes by donating directly to the organisations working to protect them or you can share articles, social media posts and news stories on the latest research and legal actions:
Make them visible by helping scientists and researchers get their news and research out into the world!
Did you know that the North American red fox is not the only red fox listed as endangered?
The red fox (Vulpes vulpes peculiosa) in Korea, is listed as a Class I endangered species by the Ministry of Environment of Korea and has been considered to be extinct in South Korea since the 1980s, with extensive management plans now in place to ensure their repopulation and survival;
"An intensive restoration project has been underway in Sobaeksan national park. This study was carried out to develop a suitable model for the red fox reintroduction program based on Population viability analysis (PVA) by using the VORTEX program.
If 10 animals (5 females and 5 males) were continuously released into the initial zero population every year for 10 years, population growth rate and extinction probability over the next 50 years after the introduction of the population were 0.018±0.204 and 0.354, respectively; the maximum population size was 116.34 at the 16th year after the first release, and a reduction rate of 1.22 every year from the 17th year was inferred.
We found that additional releases would be needed from the 17th year after the initial release to maintain a positive growth rate and to prevent the extinction of the released red foxes, and releasing more than 12 individuals every year would be needed for the long-term, continuous existence of red foxes. By contrast, if fewer than 6 red fox individuals were released the extinction probability over the next 50 years was more than 80%.
To maintain the minimum population growth rate, the release of more than 8 individuals were needed for positive population growth. The population growth rate was more stable when 10 animals in the change of their sex rate every year from the set value were released as the female-to- male sex ratio of 6:4 rather than 1:1. However, if the female-biased sex ratio was increased by more than 7:3, a negative population growth was expected. The occurrence rate of roadkill and poaching are important factors in the red fox restoration project.
The extinction probability was decreased to 30% if each factor was decreased to 3% based on the standard baseline; however, if each factor was increased to more than 3%, an extinction rate of about 90% was reached over the next 50 years."
Species Restoration Technology Institute, Korea National Park Service, 2013.
Despite generally being considered one of the least threatened species on the planet (and wrongly being considered native or non-native through history across the globe), the red fox has fought hard to remain thriving alongside man.
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