The Fabulous Foxes of California’s San Joaquin Valley

As nighttime falls on California’s San Joaquin Valley, two large pointy ears appear above the sparse grasses. In a flash, a tiny fox jumps into action and begins chasing down its prey.

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Chuck Graham

San Joaquin kit foxes are the smallest fox species in North America, measuring only about 12 inches tall and weighing up to 5 pounds when fully grown. These tiny foxes, known for their oversized ears, bushy tail and curious nature, play a large and vital role in the health of their ecosystem. But they and their habitat are in serious peril.

Let’s jump into some amazing facts about the San Joaquin kit fox, uncover what threatens them — and their habitat — and find out what you can do to help them!

What Do These Foxes Eat and What Role Do They Play in Their Environment?

San Joaquin kit foxes fill the role of both predator and prey. They primarily eat kangaroo rats, mice and other small animals, helping to control rodent populations. As prey, they support larger species like coyotes and bobcats. These foxes also serve as ecosystem engineers by creating and maintaining extensive underground systems, which provide habitat for other burrow-dwelling species.  

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Rick Derevan

Aside from their vital roles in the ecosystem, the San Joaquin kit fox is an indicator species. This means their population declines may signal other nearby species are impacted by ecological threats such as habitat loss or climate change.

Into The Foxes Den

San Joaquin kit foxes are nocturnal, spending most of the day within their dens, which are typically dug by the foxes into crumbly soil found throughout the San Joaquin Valley. In fact, this fox is endemic to the San Joaquin Valley, meaning this species does not exist anywhere else in the world.

But these little foxes are in big trouble. Some estimates suggest fewer than 3,000 San Joaquin kit foxes remain in the world today. Due to their declining numbers, they are listed as Endangered under the Endangered Species Act and Threatened under the California Endangered Species Act.

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Rick Derevan

The Biggest Threat: A Shrinking Habitat

These foxes were once widespread across the San Joaquin Valley’s grasslands, but habitat loss, predation and human encroachment have drastically reduced their range. In fact, by the 1930s, their range had been reduced by more than half. Today, almost 95% of their original habitat has been converted to housing, agricultural uses, roads, aqueducts and utility-scale solar energy development.  

This reduction in habitat not only shrinks the areas where the foxes can live but also creates "pinch points" that limit their movement and fragment populations. When habitats become isolated due to development, foxes can no longer move between different areas to find food, mates and shelter. This isolation can lead to inbreeding, reducing genetic diversity and making the population more susceptible to disease and other threats. Ensuring kit foxes do not become genetically isolated is crucial for maintaining healthy and diverse populations.  

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Rick Derevan

Maintaining connectivity also allows these foxes to adapt to changing environmental conditions. As climate change and human activities continue to alter their habitat, the ability to move freely across the landscape will be essential for their survival.

The Solar Dilemma

While any development has the potential to negatively impact this species, Defenders of Wildlife focuses on impacts to San Joaquin kit foxes from large-scale renewable development. We strongly support electricity generation from renewable energy sources because a low-carbon future is vital for alleviating climate change impacts. However, we must be mindful and balance the need for renewable energy with protecting sensitive species and their habitat.  

The utility-scale solar development footprint is exploding within the San Joaquin Valley. Utility-scale solar projects, also known as solar farms, can range from a few hundred acres to over 10,000 acres. As the number and size of solar projects increase, so does the loss, degradation and fragmentation of crucial habitat. To avoid unintended consequences and impacts on the foxes, these large-scale solar projects should not be placed in important San Joaquin kit fox habitat or within areas that serve as connectivity corridors for the species.  

To reduce impacts on San Joaquin kit foxes, project developers are often required to acquire compensatory mitigation land, which is permanently protected and managed for conservation in perpetuity. Developers need to more thoughtfully acquire these mitigation lands in order to strategically link large areas of habitat for connectivity; not piecemeal mitigation lands on a project-by-project basis. The latter will only create undesired pinch-points instead of the habitat connectivity this species needs.

You Can Help These Foxes

San Joaquin kit foxes cannot speak or vote, but we can do so on their behalf. Encourage your local government officials to be more thoughtful about the amount of protected habitat needed to mitigate impacts from solar energy development. Speak up to decision-makers and remind them to prioritize the acquisition of mitigation lands in locations that ensure continued or restored habitat connectivity for the species. You can also support organizations like Defenders that work tirelessly to protect San Joaquin kit foxes and their habitat.