Natural History

Several years ago, I wrote a post called  “The Tale of Two Foxes in West Virginia.

In it, I used information from the best research at the time to tell what was the supposed story of red (Vulpes vulpes) and gray (Urocyon cinereoargenteus) foxes in in West Virginia. In the post, I claimed that the only reason why there were red foxes in West Virginia is because they were derived from English red foxes that were introduced to the Chesapeake Bay region in the seventeenth century. The reds were able to spread because the forests were cleared into agricultural land, and in parts of Europe, red foxes prefer to live in agricultural land. Gray foxes were always native, but because they are tree-climbers, they don’t feel as secure in more open places.  So their population declined.

Now, I have long believed this story to be the full story of the two species. It was certainly true that red foxes were here during the Pleistocene, but they were gone by the time Europeans arrived.

But the claim that red foxes were all derived from English imports has certainly been drawn into question with the recent publication of a study of red fox mitochondrial DNA.  This study found that red foxes in the East and South had mtDNA haplotypes that were most closely related to those of Eastern Canada. There were no Eurasian haplotypes found in eastern North American red foxes.

This means that, at least in terms of its maternal inheritance, the red fox of the East was derived from an indigenous population.  The researchers posit that the red fox was able to colonize the Eastern US following the development of agriculture, which allowed red foxes to come pouring down from Canada and northern New England.

Now, we certainly need more analysis from more of the red fox genome than mtDNA, but it does indicate that red foxes may not be derived from imports at all.  It’s unlikely that the Tuckahoes of Virginia and Maryland would have ever been able to import that many red foxes. It took a weeks to cross the Atlantic, and any foxes that survived the journey may not have been hardy enough to survive in the Chesapeake Bay region. English foxes would also have very little immunity to subtropical parasites and diseases, which would have been common in the region. There is also more than a century of time between when red foxes became common in the East and when the the introductions of foxes by the tobacco aristocracy.

The only real problem I have with some of these studies is the assumption that European-style agriculture alone was the main factor in establishing the red fox in the Eastern United States.

I think there is a factor that very few scholars have examined.

And it’s one that comes to me from a story from my grandfather.

As regular readers of this blog know, my dad’s family was deeply involved in fox trapping when fur prices were high in the late 60’s and early 70’s.

One of the ways to set a fox trap is to bury a bit of meat from a typical prey species as bait for the trap. The meat would be buried just above where the trap was set. And the old trick was to sift the dirt from a pissant mound over the trap. Pissants produce a natural antifreeze when they build their mounds, and because it is natural, the foxes don’t think anything about its smell. Frozen traps simply won’t work.

To attract the fox, a few drops of red fox urine would be dripped on the dirt where the bait was buried. When foxes bury a bit of prey, they often urine mark above it.

In this way, the set resembles where a fox has set up its own cache, and when a fox of either species comes across another’s cache, they aren’t above stealing it. And the way they raid a cache is to dig it up, but when they dig up one of these mock-cache sets, they get caught in the trap.

Now, one could buy urine from from a trapping supply catalog, or you could collect your own.

My grandpa decided to collect his own.

He trapped about a half dozen red foxes and put them in a cage with wire flooring.  Beneath the flooring was a tarp that was spread out and elevated so that the urine ran down. In the center of the tarp, a hole was cut. Into that hold was a metal funnel that channeled all that urine into a container.

In order to keep the urine natural, my grandpa fed them groundhogs and rabbits that he shot for them. Had he fed them dog food or table scraps, the urine would have lost its natural smell.

So he kept these red foxes for their urine, but one day, he caught a gray fox and decided to add it to his “piss fox” collection.

He put the gray into the fox cage, and all hell broke loose.

The gray attacked all the reds, and it was in the process of killing one of them, when he managed to jerk the gray fox out of the cage with his catch pole.

He had read in trapping manuals that gray foxes tend to dominate reds, and one normally doesn’t find the two species in the same place.

He had also noticed that when he called foxes in to the gun at night, he could never get a red fox to respond to a gray call. Gray foxes would come in on a red call, and of course, reds would approach the calls of their owns species.

So when he called foxes, he used only recordings from red foxes.

Now, the notion that gray foxes dominate reds has only recently worked its way into the literature. Throughout their range, red foxes dominate all other foxes, which they usually have outclassed in terms of size. In the Eastern US, red and gray foxes are actually about the same size. In this area, the reds tend to be a bit smaller than normal, and the grays are a bit larger.

What does this have to do with the “real story” of foxes in the East?

Well, check out this map. It shows the likely range of red foxes at the time of Columbus:

This comes from study I already referenced that showed that red foxes in the East had no Eurasian mtDNA haplotypes.

This study, like many others, thinks the main reason why red foxes came to dominate in the East is that the forests were cleared to main European-style agricultural regions, which the foxes were more adapted to.

However, here’s a map of the ecoregions of North America:

If you look at the key of what each of these regions are, the red fox in eastern Canada was found in forested regions before the time of Columbus.

So there has to be another factor.

And I think that factor is the gray fox.

Now, you may be thinking that this is a bit of a bold claim on my part.

And it certainly is.

But there is another recent mtDNA study that leads me in this direction.

This study was a comparative analysis of mtDNA haplotypes of gray foxes in the East.

It found that gray foxes have only recently colonized New England and most of New York State.

Their populations expanded into the Northeast and Canada during the Medieval Climatic Anomaly, but their range contracted during the Little Ice Age.

The first English settlements in what became the Eastern United States were during the Little Ice Age.

In the East, gray foxes are very much connected to the deciduous forest. They could expand their ranges to northern forests, but as a species, they simply aren’t as adapted to living in very cold climates as red foxes are.

Just for a reference, here is the current range map for gray foxes:

If you look at the map of the red fox’s range in the East, there appears to be a very inverse correlation between red fox and gray fox ranges, and if one realizes that the gray fox’s range has only recently expanded into northern New England and Quebec because of global warming, the gray fox seems more and more like a likely culprit in holding back the red fox in the East.

If we think about it, the gray fox as the limiting factor for the red in the East would fit with what we already know. During the Pleistocene, red foxes were found in the East as far south as Virginia.

And gray foxes had a much more restricted range during that same time.

But at the end of the last glacial maximum, gray foxes expanded north, pushing red foxes up into northern New England, Quebec, and the Maritimes.

When Europeans arrived, the felled the vast deciduous forests, destroying gray fox habitat.

And gray fox numbers were reduced.

And this is the factor that allowed forest-dwelling red foxes from Northern New England, Quebec, and the Maritimes to come south.

It was not the felling of the forests alone. It was what the destruction of the forests did to gray foxes that became the main factor in the red fox’s success in the East.

Now, the forests in much of the East are coming back, especially in New England and Appalachia.

This has proved to be good news for gray foxes– and it is probably bad news for reds.

Of course, it might be a bit touchy to say that red fox numbers, which have been declining in recent years, are the result of gray foxes coming back. Coyotes are also moving in, and they do limit red foxes where their ranges overlap. Grays are also much better adapted to living where there are coyotes. Grays can climb trees to escape coyotes. Reds cannot.

But it seems to me that much of the scholarship on red foxes in the East has largely ignored the factor of gray fox domination.

Almost all trappers and fox callers know that the gray dominates the red, and the red’s fear of the gray is a major factor in its behavior.

But fox researchers really haven’t considered it.

The research on the gray fox is generally poor anyway. It’s hard to observe, and it’s not endangered.

And because red foxes normally dominate and kill foxes of other species, it is a bit of a turn of events to see the red fox dominated by the Urocyon.

It’s just one of the weird things about gray foxes.

They climb trees.

And they beat up red foxes.