Scientists know that Europeans brought red foxes to North America, probably to hunt, while other red foxes escaped into the wild from fur farms. But are some red foxes found on the East Coast and in North Carolina native?
According to wildlife genetics expert Liz Kierepka, the answer to this mystery lies in their DNA.
The Abstract spoke with Kierepka, who has a joint appointment at NC State and the North Carolina Museum of Natural Science, about what we know so far about the origin of red foxes, Vulpes vulpes, in North Carolina and in the Americas. of the North in general. .
The Summary: Are There Native Red Foxes in the Southeast?
Liz Kierepka: Based on genetic studies, we believe that the vast majority of red foxes in the Southeast are native to North America and mostly belong to a line of foxes known as the Eastern lineage. The eastern lineage is one of three relatively well-established and genetically distinct red fox lineages in North America. All of these lineages diverged during the Ice Age, and today we can see differences in their DNA. There is also another group in Alaska that is more closely related to the Asian red foxes.
We know that there was an introduction of European red foxes to the mid-Atlantic region of the eastern United States. There is a higher proportion of non-native foxes in Virginia and Maryland due to that introduction, dating to around 1700. Foxes were also bred for their fur, and many foxes escaped or were released. Many of those foxes interbred with our native foxes.
TA: How far back do foxes go back in North America?
Kierepka: Red foxes originated in the Middle East and then spread throughout the world. They crossed from Eurasia over the land bridge between Russia and Alaska about 400,000 years ago. When the Ice Age occurred, previous habitats were covered in ice and the foxes had to reorganize in areas without glaciers. Due to the glaciers, certain fox populations were no longer in genetic contact. They then evolved into the genetically different groups that you can still see today.
TA: How do you know all this?
Kierepka: Red foxes have been the subject of many genetic studies over the years. Researchers at the University of California, Davis were able to identify the three genetically distinct groups of red fox in North America by studying their DNA. The more differences that occur in their DNA sequences, the more differentiated the animals will be.
In these genetic analyses, the researchers looked at the DNA of the mitochondria. Mitochondrial DNA is good for building phylogenetic trees because it often reflects the isolation that occurred during the Ice Age. Mitochondrial DNA is much easier to obtain than nuclear DNA. There is one nucleus per cell while there are hundreds or thousands of mitochondria. You can get DNA from hair samples, fecal samples, or even saliva.
TA: What about the red foxes in North Carolina? Are they native or were they introduced?
Kierepka: The thing with red foxes in North Carolina is that we haven’t really looked closely at the population here. In the study that characterized red fox genetics for North America, there were only a handful of specimens from North Carolina. Of the few samples they tested, one was likely from a fur farm and two were native. There are probably native foxes here, but we don’t know how often. We just don’t have enough samples.
There are historical records where people would speculate on this question. They suggested the possibility of the introduction of European foxes, but these are from records from the early 1800s and 1900s. There are various accounts that say they may have been brought in, but these records are difficult to verify.
TA: Why is it important to try to answer questions like this?
Kierepka: It’s important to understand how species can adapt to new environments. When invasive species enter, it can cause invasive and native species to breed together. This interbreeding can disrupt populations that are adapted to certain environments.
In California, for example, non-native foxes do very well in human-dominated landscapes, while native foxes prefer undisturbed habitats. Some of these native foxes are on the verge of extinction due to habitat loss and climate change. We could lose some of this genetic diversity that we didn’t know existed until we looked. I don’t know if that’s happening in North Carolina or not, but we’ll only know if we study it.
In conservation, one of the goals is to preserve as much genetic diversity as we can because it can help species adapt in the future with habitat loss and climate change.
TA: Are gray foxes and red foxes the same species?
Kierepka: Gray foxes are the oldest canids in the dog family. They are so different from red foxes; I would be shocked if they hybridized. It’s like a rat and a squirrel mating successfully.
Tree cover helps gray foxes coexist with coyotes in the field
Mark J. Statham et al, The Origin of Newly Established Red Fox Populations in the United States: Translocations or Natural Range Expansions?, Journal of Mammalogy (2012). DOI: 10.1644/11-MAMM-A-033.1
Provided by North Carolina State University
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