Creature Feature: San Joaquin Kit Fox

Although the San Joaquin Kit Fox (Vulpes macrotis mutica) can easily be mistaken for other canids such as the red or grey fox, they are their own unique species with an interesting history. Unlike coyotes or other foxes, these slender, miniature foxes are endemic to the San Joaquin Valley of Central California. As the smallest fox in North America1, they possess skinny limbs, a long bushy tail, and wide “satellite dish”-like ears. To blend in with their grassland surroundings their coat color varies both temporally and spatially, from a tan brown in the summer to a deeper gray in the winter. On average, individuals measure just over 2 feet in length, and are similar in size to a large housecat. In the local food chain, these foxes are so small that their main predators are either the red fox or the coyote2.

KitFoxPhoto1
A lone San Joaquin kit fox found in its natural grassland habitat. [Source]
Historically, the distribution of these foxes was expansive in California and ranged across all corners of the San Joaquin valley. Typical of this valleys’ landscape, sprawling grasslands provide an ideal habitat for these kit foxes, as looser soils allow them to easily dig underground burrows. Burrows provide foxes with shelter and protection for their offspring, and hence are critical to their overall fitness and survival3. These burrows are so important for the San Joaquin kit foxes that state law urges that any burrows that might be used by kit foxes are not to be filled or destroyed4.

KitFoxPhoto2
A kit fox adult and pups found in front of their burrow. [Source]
Despite their historically expansive range, an increase in urban development over the last century has led to extensive habitat fragmentation and destruction throughout the San Joaquin kit foxes’ range5. Additionally, high levels of pesticides from Central Valley farm runoff has greatly affected the health of local groups of foxes6. A rapid decline in the overall kit fox population from the 1930s to the 1960s placed them on the endangered species list, where they still remain today. Unfortunately, even after 50 years of bearing the badge of a species doomed for extinction, their population numbers continue to decline.

Interestingly enough, these foxes have taken to the streets of some Central Californian cities. In cities like Bakersfield, San Joaquin kit foxes have lost their wariness towards humans and have infiltrated their backyards. With a lack of predation pressure from coyotes in these open urban areas, kit foxes are able to thrive and take advantage of the plentiful food resources that cities have to offer7. These small critters mostly come out at night and cruise through golf-courses and parking lots looking for delicious grub. In fact, the people of Bakersfield have taken a liking to their newly-urban furry friends, and often put food out for them like stray cats. Although this is a kind gesture, scientists have warned against this since it exacerbates the prevalence of kit foxes in cities and perpetuates the loss of their natural inhibitions and fear of human settlements. In fact, the state of California has issued some guidelines8 for how to minimize attracting and interacting with kit foxes in areas of human settlement.

BakersfieldPhoto
Night skyline of Bakersfield California. This is just one of the Californian cities that San Joaquin kit foxes have invaded. [Source]
Even though these foxes face a myriad of threats, the state of California is taking action to help protect these small California mascots. Scientists at the California State University at Stanislaus, as well as the U.S. Fish and Wildlife Service, have engaged in Endangered Species Recovery Programs for San Joaquin kit foxes4. These programs release suggestions for mitigating threats to these kit foxes, as well as recommendations on how to handle foxes that have become entangled in urban structures (such as sports netting) or those that have become injured. As responsible California citizens living in these areas, it is our duty to be aware of the threats that humans pose to these endangered animals and what we can do to minimize the human impacts on the larger San Joaquin kit fox population.

[By: Josie Hubbard]


References:

  1. S. Environmental Protection Agency (February, 2010). Endangered Species Protection Plan: San Joaquin Kit Fox. Retrieved from https://www.epa.gov/sites/production/files/2013-08/documents/san-joaquin-kitfox.pdf
  2. Ralls, K., & White, P. J. (1995). Predation on San Joaquin kit foxes by larger canids. Journal of Mammalogy76(3), 723-729.
  3. Koopman, M. E., Scrivner, J. H., & Kato, T. T. (1998). Patterns of den use by San Joaquin kit foxes. The Journal of Wildlife Management, 373-379.
  4. Cypher, B., Van Horn Job, C., Phillips, S. (2012, January 16). Conservation Strategies for San Joaquin Kit Foxes in Urban Environments. S. Bureau of Reclamation. Retrieved from http://esrp.csustan.edu/publications/pdf/cypher_etal_2012_urban_kitfox_conservation_esrp.pdf
  5. Cypher, B. L., Phillips, S. E., & Kelly, P. A. (2013). Quantity and distribution of suitable habitat for endangered San Joaquin kit foxes: conservation implications.Canid Biology and Conservation16, 25-31.
  6. Miller, J. (February, 2006). Poisoning our Imperiled Wildlife: San Francisco Bay Area Endangered Species at Risk from Pesticides. Center for Biological Diversity. Retrieved from http://www.biologicaldiversity.org/publications/papers/bayareapesiticidesreport.pdf
  7. Newsome, S. D., Ralls, K., Van Horn Job, C., Fogel, M. L., & Cypher, B. L. (2010). Stable isotopes evaluate exploitation of anthropogenic foods by the endangered San Joaquin kit fox (Vulpes macrotis mutica). Journal of Mammalogy91(6), 1313-1321.
  8. Guidelines for minimizing contact with kit foxes: https://www.wildlife.ca.gov/keep-me-wild/kit-fox

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