Living with wildlife: Will the fox avoid domestication?

By Gary Raham
Nature Writer

I've seen several foxes this year, two near Wellington. This is not too unusual, as foxes like an open habitat with a scattering of bushes and trees not unlike the typical residential neighborhood.

It's fun to spot the splash of orange of a red fox (Vulpes vulpes) as it dashes across the road, feet and ear tips trimmed in black. During one encounter I was car-bound on a side street. I stopped to admire the amply furred animal and it, seemingly more curious than prudence would demand, lingered for several minutes to take the measure of a silver-topped primate. In the second encounter, a much skinnier animal bolted away from the squashed remains of a bull snake while I was still some 50 yards away. Such a range of personality traits has provided scientists with a glimpse of how wolves transformed into our domesticated partners so long ago, and how the fox might travel in their paw prints in the future.

Red and gray foxes in Colorado are typically 3 feet long and weigh 9 to 11 pounds. The red fox displays the colors described above and sports a bushy, white-tipped tail. The gray fox shows almost a reversed color pattern with black-tipped tail and darker fur with reddish accents on the feet and ears. Both are active mostly at dawn and dusk as they search for a tasty rabbit or mouse. They will also eat other small mammals, birds, insects, snakes, carrion and a bit of fruit (especially raspberries, I understand) for variety. Coyotes consider foxes competitors and potential food.

A red fox is ready to breed when 1-year-old and a female, or vixen, has a single litter of four to five pups per year after mating in January or February with a male who is monogamous - at least for one season. The parents raise their pups together, but then split up in the fall and may get together again the following year.

Foxes are not especially dangerous to people, although they will bite and are subject to rabies and a mite-induced disease called mange--especially when populations rise during good years. People prize fox furs and because of that, foxes have been "farmed" since the early years of the 20th century. This practice formed a pool of animals in Russia that led to an amazing experiment in the roots of domestication led by geneticist Dmitry K. Belyaev. Though Belyaev is now gone, his work continues nearly 50 years later.

Devoted as collies, independent as cats

Farmed foxes are by no means tame, but they will tolerate being caged. Around 12 percent are noticeably more comfortable around people. Belyaev began with a farm population of 30 males and 100 vixens and decided to select solely on the basis of tameness. (Completely wild foxes often appear almost psychotically frenzied when caged, often injuring themselves trying to escape.) At 7 to 8 months old, when the foxes became sexually mature, researchers scored them for tameness and placed them into three classes. Class III animals either fled from people or bit them when stroked or handled. They did allow hand feeding, however, which made them tamer than wild foxes. Class II animals could be petted and handled but showed no emotional attachment to people. Class I animals displayed friendly behavior toward people, including tail wagging and whining.

After six generations of breeding Class I animals, a "domesticated elite" appeared (Class IE) "eager to establish human contact, whimpering to attract attention and sniffing and licking experimenters like dogs."

By the 10th generation, 18 percent of pups graded as elite. By the 20th generation, the figure had reached 35 percent. In 1999, the figure had reached 70 to 80 percent.

Even more amazing, a set of physical characteristics followed along with the selection for behavior. They include the appearance of dwarf and giant varieties, piebald coat color, wavy or curly hair, tails that curl like a dog's, shortened tails with fewer vertebrae, floppy ears and a willingness to breed throughout the year.

The selection for tameness affected broad developmental and hormonal systems. The domesticated elite showed a delayed fear response linked to when plasma levels of important adrenal hormones spiked. After 12 generations, basal levels of adrenal hormones halved, then halved again after 30 generations. Brain chemistry altered, too. Serotonin levels rose, inhibiting aggression in the same way it does in people taking Prozac. In general, to become domesticated involves expanding childhood--or puppyhood--and throttling down the stress responses that allow survival in the uncertain wild.

In 1999, the Russian economy forced a reduction in research funding. Researchers reduced Belyaev's breeding herd from 700 to 100 to make use of available funds and were considering marketing some pups as house pets. Although I haven't heard how that venture faired, I think I prefer watching the wild variety of fox - the one that views me, as it probably should, through slitted eyes and a fully charged adrenal system.

If I need companionship, I can always pet a dog or wave at a cat.