Canis lupus hominis

Video is here.

Swift foxes are prairie animals. They went extinct in Saskatchewan, Manitoba, and Alberta because of the practice of lacing carcasses with strychnine and other poisons to kill wolves. These poisons would kill any animal that scavenged the carcass, including swift foxes.  There are several other reasons listed here. The decision of Canada to tame its prairies for agriculture made it an inhospitable place for the swift fox.

The Smeeton fox breeding mentioned in this video is now run as a private organization. Their daughter, Clio, is probably the world’s greatest authority in swift foxes. The use of tribal lands in this part of Canada has been key to restoring them to the wild. Also, they have bred the foxes in open air pens, where they are occasionally preyed upon by hawks. This predation teaches the kits to avoid birds of prey, a very useful skill in the wild. However, I don’t know how any fox can learn to avoid coyotes from a captive situation.

These foxes are really interesting. Its scientific name is Vulpes velox, placing it in the genus of the “true” foxes, including the red fox.  It has a very close relative called the kit fox (Vulpes macrotis–“big eared fox”). It ranges into the deserts of the United States– Southwest and Great Basin– and Mexico. Its range is a bit west of the swift fox.

At one time, they were considered conspecific. Indeed, they have interbred and produced fertile offspring. Some people refer to the swift fox as a “kit fox,” but the current thinking of taxonomists is to place them as separate species.

Interestingly, their closest relative is the Arctic fox, with whom they both share the same number of chromosomes and a common ancestor within the last 250,000 years. However, the Arctic fox is usually classified in its own genus called Alopex.  This genus exists because the early taxonmists relied upon morphology alone to determine relationships between animals. The Arctic fox had a skull that was broader than a typical fox in the genus Vulpes but narrower than a dog’s skull. So it had to be a separate genus.

Now, we know that Arctic foxes are really closely related to the kit and swift foxes. In fact, if you look at white form of Artic fox in the summer and compare to the swift fox above, you can see a very strong similarity. (White Arctic foxes are brown with cream-colored patches on their necks, chests, bellies, and tails. They turn white in the winter. Blue Arctic foxes are silvery black in the summer months or silvery black with white markings. They turn a grayish blue color in the winter.)

White Arctic fox in summer. Compare with the swift fox above.

No one would have ever thought that the desert dwelling kit fox and the Arctic fox were such close cousins. In fact, it was only when fur farmers in Scandinavia crossed “blue foxes” with “silver foxes” that science began to realize the taxonomy wasn’t quite right. Blue foxes are the blue phase of Artic foxes, which are highly prized for their fur. Silver foxes are melanistic red foxes that have interspersed gray hairs on their coats, giving them a silver appearence. These hybrids were infertile, but it raised the question about whether the Arctic fox was truly a separate genus from the other foxes.

As far as I know, no one has tried to cross an Arctic fox with a Swift or kit fox, but it is probably possible. It is also possible that they could produce fertile offspring from the cross. However, kit and swift foxes aren’t fur farmed animals. There are no “domestic” strains of these foxes, unlike the various domestic forms red fox (including the truly domesticated foxes of Russia) and the farmed variety of blue Arctic fox.

Of course, I’m sure the first people to lay eyes on a swift or kit fox thought that it was a gray fox. However, the animal called a gray fox in North America isn’t even closely related to the true foxes. It is gray, just as the swift and kit foxes are, but it is an entirely different animal. It is the oldest canid in the Americas, and it may be the oldest canid in the entire world.

Its closest relative can be found on the Channel Islands. This species of fox is called the island fox, and it resembles a very small gray fox. How it got to the islands remains a mystery, but one theory is that it arrived there as a pet belonging to the native peoples of Southern California. Because it was living on the islands, where food was somewhat scarce, the fox became smaller and smaller to make better use of these limited resources. Today, it is a highly endangered animal.  These two foxes are not closely related to the others, and they aren’t related to any of the South American “wolf-foxes” either. They are an evolutionary relict of what the first wild dogs may have looked like.

The swift, the kit, and Arctic foxes should probably be placed in the same genus, which the share with the other Vulpine foxes, including the well-known red fox. The fact that we are only just now figuring out where these animals fit into their proper taxonomy and evolutionary history shows the limits of using morphology alone to determine these relationships.