A San Joaquin kit fox on a Bakersfield lawn | Photo: CSUS ESRP / Tory Westall If I were to ask you where I could find a healthy population of the endangered San Joaquin kit fox, you might be forgiven for not immediately saying, Why, Bakersfield, of course!
Bakersfield? The Oil Capital of California? Why yes, the very same! Unlikely as it seems, this city sprawling at the southern end of the Central Valley, butt of bad jokes and dark fiction in Hollywood and home to nearly half a million people, has also become a refuge for a growing population of Endangered San Joaquin kit foxes.
This subspecies of the kit fox found throughout the deserts of the American Southwest is named after its native San Joaquin Valley home, which it has mostly lost to farming and urban development over the last century. Its population declined so drastically that it became one of the first species to be officially listed as Endangered by the federal government in 1967. Its cousin, the Southern California kit fox went extinct in 1903, and the San Joaquin kit fox has been pushed to the outer margins as humans transformed the Central Valley into the agricultural engine of California. The little canid has seemed like a permanent member of the endangered species list through nearly half a century.
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In addition to losing habitat, the subspecies also suffered from changes in populations of other carnivores in California: the big bad wolf was extirpated from the region, allowing the smaller coyote and bobcat populations to grow. This was bad news for kit foxes because both these larger predators prey on them. The introduction of non-native red foxes also meant greater competition for already diminishing habitat. It seemed like a classic case of a species being pushed to the brink by an extinction vortex driven by direct and indirect human impacts. But surely the most visibly extreme way humans destroy native habitats is by building cities. So how does a little kit fox manage to live and indeed thrive in the middle of this urban sprawl?
By the late 1990s, wildlife biologist Brian Cypher of the Endangered Species Recovery Program in California State University, Stanislaus knew there were a few foxes in Bakersfield, stragglers he thought, that had somehow managed to not die amid development. Watching them more closely, he started noticing that the same individuals (with visible markers identifying them) were apparently holding down home ranges for long periods of time. He started noticing pups, which meant they were also reproducing. Were they establishing themselves in the city? Thus began Cypher's long-term research on these urban foxes, which continues to surprise the veteran conservationist.
Just like the humans who build cities, the kit foxes, it turns out, find urban habitats to be safer and more nourishing than the surrounding countryside. The lack of large urban forest patches or wooded areas means that unlike their Chicago cousins, Bakersfield coyotes avoid the city; so do bobcats. The city also provides an endless smorgasbord for a small omnivorous predator, ranging from junk food in garbage tossed out thoughtlessly by some people to more nutritious dog and cat food intentionally supplied by others who actually like having the kit fox around in their neighborhoods.
So, it turns out, the big bad city is actually not such a bad place for an endangered kit fox to raise a family, or several. And they do just that, in abundance. Cypher's research indicates that while only one in ten of the pups born in the countryside survive past the first year of life, over half of the urban pups survive in Bakersfield. This drop in first-year mortality is one reason why the kit foxes are thriving in the city, with population densities much higher than outside. While a single pair may occupy two square miles of countryside, in Bakersfield, Cypher and his team have identified (using camera traps) more than 30 individuals living on the local California State University campus alone. Across the city, he estimates a population of 400-500 kit foxes, and growing, making Bakersfield home to their 3rd largest remaining population.
Carnivores generally don't fare well at high densities. Island Foxes stuck in high densities on on the Channel Islands, Cypher tells me, look always torn up, like they are always fighting all the time. Mainland foxes prefer to keep their distance from each other, maintaining territories through scent marking, and avoiding direct confrontation whenever possible. One might, therefore, expect more aggression among Bakersfield's kit foxes. But that is not the case here, says Cypher. The urban kit foxes turn out to be quite docile, and not as fiercely territorial or aggressive toward each other. Instead, surprisingly, they seem to be engaged in more cooperative behaviors, especially when it comes to raising pups.
Kit foxes born in the countryside typically tend to disperse away from their parents to find their own territories within a year or two. While an older pup may linger past the first year and help raise next year's brood, helpers at the den are rare. In the city, however, Cypher finds a lot more helpers, possibly because there is a steady supply of food in a saturated real estate market with few open territories for young foxes to take over. Why not stick around at home then, and help raise younger siblings? Urban kit foxes, however, seem to be going beyond just this increase in sociality which is predicted by mathematical models of social behavior. Cypher and his students have documented at least two cases where two females shared a single den, seemingly became pregnant at the same time, and successfully raised their respective litters together in the same den. This level of cooperation is unprecedented in our knowledge of the natural history of kit foxes.
In collabo
