A fox built for open ground, not cover
Nothing else on the shortgrass prairie is built quite this way. A swift fox is small and low-slung, with long legs suited to a flat-out sprint across open ground rather than to slipping through brush. Its coat runs pale buff to yellowish gray, fading to white on the throat and belly, with a black-tipped tail and dark patches flanking the muzzle. The ears are large and set wide on a rounded head, built to catch a mouse rustling in grass, not a distant howl.
Telling a swift fox from its closest lookalikes
Its closest lookalike isn’t the local coyote or red fox. It’s the kit fox, a close relative from the desert Southwest that’s nearly the same size. Kit fox ears are bigger and set closer together above a narrower, more pointed face. That’s an adaptation for shedding heat in hotter, drier country. The two species meet and sometimes interbreed in a narrow strip of eastern New Mexico and the Texas panhandle, right where shortgrass prairie gives way to desert scrub. Red fox is the easier mismatch to catch. It’s rangier, rustier in color, has black stockings on the legs, and its tail always ends in white instead of black.
A den it never really leaves
Most foxes only den to raise young. A swift fox never really leaves its burrow system. It digs its own tunnels in sandy or loose soil, usually a few meters long with two or more entrances. It also keeps a rotating set of a dozen or more dens spread across its territory. It moves between them through the year as fleas build up or nearby prey runs thin. The den isn’t just a nursery. It’s shelter from summer heat, winter cold, and the coyotes and golden eagles that hunt the open plains, and a fox rarely wanders far from an entrance it can duck into.
Life as a mated pair
Swift foxes pair up for the breeding season and often stay together year after year, denning as a couple rather than living alone between litters. After about 55 days of gestation, a female gives birth to four or five kits, usually in March or April. Both parents help feed the litter once the kits are weaned, splitting hunting duty so the den is rarely left unwatched.
Hunting the shortgrass prairie
A swift fox hunts mostly by scent and sound, moving low through grass too tall to see over. Rodents, cottontails, ground squirrels, and ground-nesting birds and their eggs make up most of the diet, with insects filling gaps and the occasional bit of fruit or grass when meat is scarce. Prairie dog towns are prime hunting ground even though prairie dogs themselves are usually too big to catch. The grass around a colony stays clipped short, giving a fox a clear sightline, and an abandoned prairie dog burrow makes a den that’s already dug.
Poisoned to the edge, then brought back
The swift fox’s decline wasn’t an accident. Strychnine and other poisons spread across the Plains in the early twentieth century to kill wolves and coyotes, and swift foxes died just as easily. By the 1930s, the species had disappeared from most of Canada and much of its old US range. Getting it back has taken decades of deliberate work, not a natural rebound. A reintroduction program that began in 1983 released captive-bred and translocated foxes into southeastern Alberta and southwestern Saskatchewan. By the mid-1990s, several hundred animals had gone out, and the wild population there tripled within a few years. Similar releases followed in Montana, South Dakota, and other parts of the northern Plains. The IUCN now rates the species Least Concern worldwide, a mark of that recovery. Even so, swift foxes still hold only a fraction of the range mapped for them a century ago.
Coyotes: rival and biggest threat
Coyotes are the leading cause of death for adult swift foxes across most of their range, and the relationship isn’t simple competition between two similarly built hunters. Wolves once kept coyote numbers in check on the Plains. Removing wolves let coyotes climb, and more coyotes has generally meant more swift fox deaths rather than less pressure on a smaller rival. Golden eagles and bobcats take swift foxes too, but coyotes do the most damage, which is part of why recovery has tracked so closely with how coyote-heavy a stretch of prairie is. A swift fox’s best defense usually isn’t speed. It’s the den close at hand and a habit of staying out of a coyote’s path in the first place.
