The Story of the San Joaquin Fox - Ava Mattis

The Story of the San Joaquin Kit Fox

By: Ava Mattis

Pictured above is a sleeping San Joaquin Kit Fox photographed by Brian Cross (Cross).

Description and Ecology

The San Joaquin kit fox is the smallest candid species in North America. Fully-grown males weigh only 5 pounds and are about 12 inches tall and 20 inches long. They are long and slim mammals with pointed noses, large ears that sit close together, and bushy tails. San Joaquin kit foxes’ coats vary depending on the season, but are typically a tan, grey, or orange.  (San Joaquin Kit Fox).

San Joaquin kit foxes have a life expectancy of only about 7 years, so they mate and reproduce at the young age of 1 or 2. They typically mate in winter, and then females give birth to anywhere from 4-7 kin. Their young usually depart from the family only four or five months after birth, although in some rare cases they may stay with their mother for a year after birth to help with the next year’s reproduction.

A kit fox in its underground den escaping the warm and humid summer ("Adaptations").

Kit foxes are nocturnal creatures, meaning they sleep in the day and are active at night. They live in underground dens where they rest during the day to evade predators and avoid temperature extremes by conserving moisture. Kit foxes change dens often during the summer months and sometimes change dens up to 24 times in a single year. These creatures hunt and consume animal prey such as rabbits, snakes, rodents, or insects (“Kit Fox – San Joaquin Valley Population").

Geographic and Population Changes

The kit fox needs arid land in order to successfully reproduce and live. Additionally, because their dens provide them shelter from predators, it is imperative that they live near loose-textured soils good for burrowing. Because of this, San Joaquin kit foxes inhabit grassland areas in the San Joaquin Valley. Before 1930, these animals roamed this valley extensively, with its range extending from Kern County all the way to Contra Costa County. However, in the 1930s this range was reduced in half. These geographic changes occurred due to habitat destruction because of the construction of new developments. Now the San Joaquin Valley kit fox lives in small, fragmented habitats that lie scattered across the valley (“San Joaquin Kit Fox”). These geographic changes also had profound effects on their population numbers which have decreased drastically.

Above is a picture depicting the range of the San Joaquin kit fox ("Keep Me Wild: Kit Fox").

Listing Date and Type

Because of this decline in their population numbers, the San Joaquin kit foxes were classified as endangered in 1967 on the US Endangered Species list. A few years later in 1971, California added them to a state list of threatened species. A recovery plan was written for these foxes in 1998 and is listed on the website for US Fish and Wildlife Services (“San Joaquin Kit Fox”). 

Cause of Listing and Main Threats

Some reasons for the listing of the San Joaquin kit fox are natural. Many kit foxes die because they are unable to defend against predator coyotes. Additionally, there may be a factor of competition because of non-native red foxes that inhabit similar areas.

However, the leading threats for San Joaquin kit foxes are human caused. Humans directly kill kit foxes by hunting, trapping, or accidentally hitting the animals as they cross major highways. However, a much more primary threat we pose to these defenseless creatures is habitat destruction or fragmentation. Kit foxes’ most favorable habitat areas, grasslands, are also ideal for developmental areas because there isn’t much present in the area that needs to be cleared for construction. The destruction of these habitats is extremely detrimental to San Joaquin kit foxes because it reduces their carrying capacity and their prey in the area (“Recovery Plan”).

An illustration of the San Joaquin kit fox ("L. San Joaquin Kit Fox")

Recovery Plan

For the purposes of the US Fish and Wildlife’s recovery plan for the San Joaquin kit fox, this animal is considered to be an umbrella species. This choice is because the kit fox is present in almost all of the natural communities used by other species protected in the plan. Hence, by protecting the San Joaquin kit fox, the US Fish and Wildlife Service will also be protecting a whole umbrella of other endangered species.

The main conservation efforts that have been enacted so far aim to create more habitat for the San Joaquin kit fox. One of the most important land acquisitions so far has been the purchase of 60,000 acres of land around the area of Stanislaus and Santa Clara counties. Also, some lands have been acquired as the result of mitigations from development projects in the area.

As for the recovery plan, it entails focusing efforts on three core populations and then conserving 9-12 more satellite populations of kit foxes. In the plan, a core population is defined as one that has a high concentration of foxes and therefore anchors the population, while a satellite population has fewer foxes in it.The plan will help these scattered populations by creating links between them so they can move back and forth between fragmented habitat sites.

Additionally, the American Farmland Trust will provide farmers with monetary compensation or incentives for conserving habitats that will house San Joaquin kit foxes. For example, some farmers will receive money for converting old farmland into new habitats to house these kit foxes (“Recovery Plan”).

What can you do?

There are many steps that we can take to help preserve and increase populations of the San Joaquin kit fox. They are listed below.

• Never destroy a burrow – they may be used as a kit fox den
•  Protest the construction of new developments along the San Joaquin valley – they can be taking away precious habitats from kit foxes
• Stop hunting or trapping kit foxes
• Drive with caution – we share the roads with kit foxes so yield if they are present

Other Resources

Listed below are some helpful links to websites to further aid your introduction to the endangered species of San Joaquin kit foxes.

•  https://ecos.fws.gov/docs/recovery_plan/980930a.pdf
•  http://explorer.natureserve.org/servlet/NatureServe?searchName=Vulpes+macrotis+mutica
• https://defenders.org/san-joaquin-kit-fox/basic-facts

The San Joaquin kit fox thanks you for your efforts and interest in conservation ("Adaptations").

Works Cited

Cross, Brian. “San Joaquin Kit Fox.” FineArtAmerica.com, fineartamerica.com/featured/3-san-joaquin-kit-fox-brian-cross.html.

“Endangered Species Recovery Plan.” CSU Stanislaus, esrp.csustan.edu/gis/maps/sjkfrange.png.

“Keep Me Wild: Kit Fox.” California Department of Fish and Wildlife, www.wildlife.ca.gov/Keep-Me-Wild/Kit-Fox.

“Kit Fox - San Joaquin Valley Population.” NatureServe Explorer, Nov. 2016, explorer.natureserve.org/servlet/NatureServe?searchName=Vulpes+macrotis+mutica.

“L. San Joaquin Kit Fox (Vulpes Macrotis Mutica),” Endangered Species Recovery Program.  esrp.csustan.edu/publications/pubhtml.php?doc=sjvrp&file=chapter02L00.html.

“Map of Kit Fox Populations.” IUCNRedList, maps.iucnredlist.org/map.html?id=41587.

“Recovery Plan for Upland Species of the San Joaquin Valley.” US Fish and Wildlife Services, 1998, https://ecos.fws.gov/docs/recovery_plan/980930a.pdf.

“Survival Adaptations - San Joaquin Kit Fox.” Google Sites, sites.google.com/a/stu.sandi.net/san-joaquin-kit-foxnp2017/survival-adaptations.