If they weren't so shy, they'd certainly be among our region's most famous inhabitants. For charisma, for sheer cuteness, kit foxes have few competitors in the wild fauna of the Southwest. But they're mostly nocturnal, and are rarely seen by our species.
Kit foxes are America's smallest canid – weighing less than a house cat, measuring less than 3 feet long – 40 percent of which is their bushy, black-tipped tail. From West Texas to Baja California, they're at home in the continent's harshest terrain. Their large, prominent ears register the night's every stir and whisper. Their eyes shine with unmistakable intelligence.
Jessica Buskirk, a graduate student at New Mexico State University, is studying kit foxes in the Chihuahuan Desert – specifically, at White Sands National Park. Her work opens new vistas in our understanding and appreciation of this remarkable, if elusive, creature.
Buskirk studies “mesocarnivores” – a class of mostly-meat-eaters that includes bobcats, skunks, ringtails and raccoons. But she has a special love for kit foxes, who've received limited scientific attention.
“This project was a dream come true for me,” Buskirk said. “Foxes are just incredible. They're charismatic. And they need so much more research done on them. That's another reason I was really excited about this project – it's novel information, that can be really useful for kit foxes.”
How does a predator the size of a Chihuahua flourish in the desert? The relatively lush, rich environs of the mountains belong to the larger gray fox. Kit foxes occupy desert basins, lowlands.
Shelter is key to their survival in stark locales.
“They are the only 'denning-obligate' canid in North America,” Buskirk said. “That means they use dens year-round, throughout their life history – for reproduction, for escaping predators, for escaping the weather. They're very complex structures.”
Kit foxes often have many “escape dens” – single holes they can dart into to evade predators. But each fox typically has a couple complex dens – with multiple rooms, and many openings – for daily life. They diligently maintain these structures, and freshly dug dirt – as well as tiny tracks and scat – around holes are telltale signs of a kit fox den.
Kangaroo rats, pocket mice, lizards, snakes and birds – all are on the menu. Kit foxes even hunt jackrabbits – though the two animals are roughly the same size. They generally take prey back to the den before eating it.
Family bonds are also central. Like their larger canid competitor – the coyote – kit foxes typically mate for life. Mates share overlapping home ranges. Males take an active role in pup-rearing, and together the pair teaches their young to hunt.
Buskirk studies kit foxes in one of the most austere, and haunting, of landscapes – the dunefields of White Sands. She's seeking insight into fox ecology in the park – and she's building on an earlier study here of “intraguild predation” between coyotes and kit foxes.
During two seasons, she trapped dozens of kit foxes, marking them, collecting blood samples and outfitting them with GPS devices. The work has yielded a trove of information. It's also given Buskirk a familiarity with these secretive animals that few others have.
“One of my favorite things about working with kit foxes is that you don't have to drug them,” she said. “A kit fox or two might be a little feistier than you like. But in general, all of them you can handle with physical restraint only. As soon as you put a hand on them, they just become very passive, very docile.”
They do sound the alarm when they're approached in a trap. Indeed, Buskirk has learned to identify, and imitate, several kit fox calls.
The foxes have “their little 'curious-slash-nervous' sound,” Buskirk said. “The moms make a little 'eh eh eh' to their pups. And they kind of make this scream-y bark sound – but I can't make that one. I'm not even going to try.”
Kit foxes coexist with coyotes in much of their range. Coyotes prey on foxes – though the ends that predation serves are unknown. Coyotes may kill foxes for food, or to eliminate competition. Diseases – including illnesses familiar to dog owners, like parvovirus – can spread among wild canids. For coyotes, killing foxes may reduce the spread of disease.
Coyotes put pressure on kit foxes in the shrublands of White Sands – the more heavily vegetated areas outside the dunefield. But in the dunes themselves – that 275-square-mile expanse of shining sand and sparse life – it's another story.
Because while coyotes may be larger, and “dominant,” kit foxes are what biologists call the “superior exploitative competitor.” They need fewer calories, and hence can flourish where coyotes would starve. When it comes to canid predators, kit foxes have the dunes to themselves.
Making it in the dunes does require some adjustments. One of Buskirk's most stunning findings is the size of fox territories or home ranges here. The typical kit fox home range is about 4 square-miles. In the dunes, Buskirk found, kit foxes have ranges of up to 60 square-miles.
Like other canids, and unlike wild cats, kit foxes apparently know that the human presence has its benefits. For duneland foxes, the park's picnic areas are a resource.
“Especially on holidays and stuff,” Buskirk said, “when they're overflowing with visitors, and people are really enjoying the dunes. I've seen steak bones and corn-on-the-cob and other things in dens. They're using what they can. They're being good little foxes and feeding themselves and their babies in any way possible.”
Kit foxes are true desert natives – the species' range closely matches the North American deserts. But our region has an interesting distinction. Kit foxes have a cousin – the swift fox, which, from Midland to Alberta, Canada, is a creature of the Great Plains. Kit and swift fox ranges overlap only in eastern New Mexico and West Texas – and the two are known to interbreed here.
With human-driven habitat destruction and fragmentation, kit fox populations are declining in parts of their range – too little is known to judge whether that's happening here. Buskirk's work will help provide a baseline.
And we can earnestly hope that this creature will endure in the Texas desert. One night, you may see one run across a quiet highway, or glimpse a pair of tiny eyes glinting at the edge of your campfire light.
