Feeds:
Posts
Comments

Posts Tagged ‘Eastern red fox’

DSC02512

It may not look very distinct, but this is a red fox track. I wish I had come across it when the snow wasn’t half-melted away and slushy. It would have been a nice photo addition to the blog.

But the best I can do is this nondescript smudge in the slush. It will do for now.

There is actually something of a taxonomic debate with red foxes these days.

For most of my life, it was accepted wisdom that all the red foxes living in the Eastern US south of the northern tier of New York State were derived from British imports that were brought over during the colonial period.

A few years ago, a mitochondrial DNA study revealed that red foxes living in the East were actually descended from the Eastern Canadian red fox population. and the same paper revealed that the historical records of red foxes in the East date only to the nineteenth century.  The red fox came from Canada and New England because it was able to live well in the newly developed agricultural lands that were fully open by that time. (Open lands are bad for gray foxes, an entirely unrelated species, which dominates red foxes, but prefers living in dense woodland. Opening up the land but the gray in retreat, which may have allowed the red to expand its range.)

Which means that our red foxes are probably not derived from colonial imports.

But more recent study reveals that North American red foxes might not only not be derived from British imports. they might be a different species from the Old World red fox, which is found throughout Eurasia and parts of North Africa.

This study, performed by researchers at UC Davis, revealed that North American and Eurasian red foxes split from each other 400,000 years ago. Unlike the previous study, this one looked a large sample of genetic material and the y-chromosome of foxes from different parts of their vast range. The red fox lineage first began in the Middle East, then spread across the Northern Hemisphere.

I am a bit hesitant to say this study inherently means that we have to call North American red foxes a new species.  All of these red fox populations are still chemically interfertile, and they essentially have the same niche. Furthermore, because red foxes don’t disperse far from their natal territories the way that wolves do, they are going to be a genetically diverse species. Indeed, smaller animals tend to have greater diversity as a species than larger ones do. The larger ones are usually fewer in number, and they tend spread out more, meaning their gene pools don’t have enough isolation to become as distinct.

My guess is that if similar studies were performed on least weasels and the weasel known variously as the short-tailed weasel, the ermine, or the stoat, we woul probably find even greater genetic variation between Old and New World populations.  They are even smaller than foxes, but like the red fox, they are found across the Northern Hemisphere.

Whatever the taxonomic findings, it is pretty clear that red foxes are native wildlife. Their remains have been found in Virginia dating to the Pleistocene. They couldn’t handle living in the gray fox dominated forests that came about at the end of the last Ice Age and retreated into northern New England and Eastern Canada, which are still too cold for gray foxes to colonize.

This track in the snow was made a native, not a colonist.

Their tracks have padded the snow, the mud, and the sand throughout the Northern Hemisphere. The Australian settlers, upset that they had no foxes to chase in the land of kangaroos, imported them for that purpose.  Their tracks graced the Outback too.

Here is an animal that is typically smaller than a pug, but through its adaptability, it has been able become settled across a huge swathe of the continents.

And with the exception of Australia, it got there with its own wandering feet.

Amazing little red dog with the black stockings and the long bushy tail.

 

Read Full Post »

Red foxes are native to North America.

They were also introduced.

That sounds like a contradiction, but let me explain.

First, we should look at the North America red fox distribution map. Red foxes in North America have several subspecies.

Click to make larger.

Subspecies number 6 is Vulpes vulpes fulva.

It was traditionally believed that it didn’t exist until the seventeenth century, when English colonists introduced red foxes for hunting purposes.

I’ve often said that red foxes are not native to most of the Eastern United States and that they all derive from imports.

The trouble is that there have been few genetic studies on red foxes in the Eastern and Southern US that have made tried to figure out exactly where they came from.

Well, it turns out that this assertion may be wrong.  A recent mtDNA study revealed that North American red foxes, including those found in the Southeastern US, don’t have Eurasian red fox mtDNA haplotypes. That means that the matrilines of red foxes living in the Eastern US are derived from indigenous vixens, most likely those from Eastern Canada that colonized the United States in the middle of the nineteenth century.

Now, an mtDNA study cannot tell us everything about the genetic make-up of red foxes in North Ameriaca, and it is possible that some of their genetic material came from imported red foxes that were introduced in the seventeenth and eighteenth centuries.

A larger sample of red fox DNA is needed to see exactly what the ancestry of these foxes actually is.

However, this study is making me reconsider some of my assumptions about the local red fox population.

It’s true that red foxes weren’t here at the time of colonization. However, red fox remains that date to the time of time of the Wisconsin glaciation have been found in Virginia and Tennessee.  When glaciers retreated, the red fox moved north in Canada, where it remained until European colonization.

The traditional account states that red foxes in the Eastern and Southern US came from those imports, but there is a large gap between those introductions in the seventeenth and eighteenth centuries and the establishment of red foxes in this part of North America in the  middle of the nineteenth century.

It is possible that our foxes have a mixture of native and European blood.

But it is also possible that the imports never really became established, or if they became established, they became swamped with native red fox blood as they came pouring down from Canada. My guess is there never were that many imported red foxes. Foxes are wild dogs, and they would not have taken well to confinement on their way from England to North America. Further, foxes that evolved to live in a benign marine climate may not have been able to thrive in a place that has such extremes in heat and cold.

Compared to wolves and coyotes, we know next to nothing about how the different populations of red fox are related to each other. We’ve only recently been able to determine how coyotes colonized Virginia through the Great Lakes and Canada, and we’ve also been able to figure out that certain propose wolf species are actually derive from recent hybridization between coyotes and wolves.

These studies looked at a lot more genetic material than mtDNA haplotypes, and we’re going to need studies like these on red foxes to determine what their exact ancestry is.

But if our assumptions about red wolves can be challenged through extensive nuclear DNA studies, then our assumptions are likely to be challenged when we start looking at red foxes.

Maybe we should consider red foxes native to the Eastern US after all.

I think we need to see how much “native” ancestry they have before making that assertion.

But this mtDNA study is certainly a major affront to the tradition account of how red foxes colonized the Eastern United States.

Read Full Post »

%d bloggers like this: