By Jessica Moreno, Conservation Science Director
It’s late morning in early May when my phone buzzes with a text message from my friend and long-time Desert Monitor Josh Skattum. It’s a black and white photo from our “UTA” camera in the Tucson-Tortolita Mountain corridor, a blurry ghost of a fox with large, pointed ears and a small animal in its mouth, trotting swiftly through a moonless desert night. “Kit fox?,” Josh types. It looks plausible… I promise to look at it more closely and confirm.
The desert kit fox (Vulpes macrotis) has exaggerated features and could easily be included in a sci-fi wildlife field guide, fitting comfortably among the illustrations of banthas, sandworms, or tribbles. They are tiny canines, just 3.5 to 6 pounds, the weight of a full-grown Chihuahua. That small package comes with oversized 3- to 4-inch-long ears that helps dissipate the heat, a fluffy tail that nearly doubles its body length, and fur packed between their toes creating custom-made sand shoes.
Their soft sandy-colored coats are sometimes trimmed in bright rusty orange as if their edges were dyed by the desert sunset. In the moonlight, you might only glimpse pale fur and a black-tipped tail that doesn’t sport the signature bold black stripe found on the more commonly seen gray fox. But the kit fox’s delicate pointy face, bright eyes, and overlarge ears give them the same playful and mischievous countenance.
Several more nocturnal photos later, and I am more confident in my ID. Josh even documents a likely burrow site. Just to be doubly sure (and for fun), I ask for the help of Raynor Vandeven, a talented photographer who builds his own custom-made camera traps to produce incredible wildlife images. He sets out to see if he can get a more photographic image for us – with almost instant success.
These photos are the first time a kit fox has triggered one of the wildlife cameras we use to monitor the movement patterns of animals that use Pima County’s wildlife corridors. These areas tend to be the most threatened by roads and development – and also exactly the kind of low desert habitat that is preferred by kit foxes. And here they are, fulfilling their special role in the Sonoran Desert ecosystem as mesocarnivores.
A mesocarnivore is a small to mid-sized mammal that eats mostly meat (50 – 75% of their diet) but also eats other things – fruits, plants, fungi, insects – and is therefore an omnivore. Ecologically, they serve a role similar to the fewer-in-number large carnivores, like mountain lions, with some differences, such as spreading seeds that help plant dispersal, influencing disease dynamics, and being able to drive community structure (the types and number of species that live in a place and how they interact with one another). The disappearance of mesocarnivores on the landscape, both in abundance and diversity of species, is a canary in the mine for ecological health.
For their part, kit foxes primarily eat cottontail rabbits and rodents like kangaroo rats for their meat course. Very rarely they will eat the jackrabbits that complete with them for size. They will also eat carrion, birds, lizards, insects, quail eggs, saguaro fruit, prickly pear fruit, and mesquite beans. When food is plentiful, they might cache their meals by burying them, squirrel-like, and marking the spot with pee – a fox’s version of the office refrigerator lunchbox post-it note: My Lunch. Do Not Eat.
Kit foxes are solitary hunters and are often seen alone but are part of small family groups of parents and their young. Mates form a monogamous, permanent bond and both parents care for a single litter of 5 to 7 kits, or pups, that are born blind in March and April and remain in their cool den, with its keyhole-shaped entrance, until the monsoon arrives in June or July.
They can find food and mates, raise young, and disperse surprisingly long distances to new habitats – despite the challenges of mange caused by rodenticides, canine distemper and rabies, and the very pressing concerns of habitat loss, habitat fragmentation, and wildlife-vehicle collisions. Time will tell if rising temperatures and other threats prove too much, or are averted too late, for a species that has been with us since the Great Ice Age and survived the extinction of the larger Pleistocene megafauna.
Photo by Raynor Vandeven
Today these tiny, playful desert den dwellers are considered vulnerable in Arizona but do not have any protected status. Their distribution is extensive throughout the Great Basin, Sonoran, and Mojave deserts, but populations have generally been declining by 10-30% across their range, according to data collected on NatureServe. A fox to watch.
Our nocturnal kit foxes continue to bless the desert night with their yips, barks, and chuckles. Tonight, I allow myself to imagine that they sometimes gaze up at the stars, above the haze of nearby city lights and horizon of creosote, stars that for untold generations have been their only constant. The chuckle in the dark desert night I hear sounds like an echo of Josh’s laugh.
Kit fox habitat (in bright green), in eastern Pima County, along with two of our wildlife linkage study areas in the Tucson-Tortolita Mountains wildlife linkage and the Catalina-Tortolita Mountains wildlife linkage.