Thursday, September 22, 2011

Invasive Species: Red Fox

A European red fox (Vulpes vulpes)
The red fox is an invasive that has likely caused or has a great part in the decline of numerous animals in both Australia and North America, including more than a few extinctions. However, the true impact of the species is complicated to determine as there are likely other factors that have led to the loss of those prey species. Though there isn't much competition seen between the red fox and other species, it is believed that qoulls in Australia are being negatively effected. The red fox is also known to take livestock (as in chickens and young sheep and goats) and is a potential carrier for rabies. Fox pelts are a large part of the fur industry, for which they are raised on farms. I would imagine that the several color varieties make the species especially attractive to the industry.

This species is native to a very large area: Europe and virtually all of Asia, plus parts of North Africa and North America. They have been introduced to Mexico, Canada, the United States, and Australia. Due to the addition of this introduced range, the red fox is easily called "the most widely distributed carnivore in the world."

Numerous methods have been and continue to be used in attempts to control the red fox population, especially in Australia. Poisoning, shooting,  fencing, and trapping have all been used, but recently there has been more concentration on trying to limit the foxes' abilities through baiting. These baits may include poison, vaccines, or something that effects fertility, which reduces the number of young born. In Australia, the poison used is derived from a native plant that native species can tolerate so as to only kill the invasive. Exclusion fencing can also quite useful if constructed in the right manner.

The red fox is on the list of the 100 World's Worst Invasives at #99.

Image is from Wikimedia Commons under a creative commons license.


  1. In my part of the country, there are native red foxes and introduced ones, and they've sort of blended. The introduced ones are far more common, but the ones that are of native ancestry are larger and have less black on their legs.

  2. BTW, this is slightly in error. The most widely distributed Carnivoran is the domestic cat.

  3. The most widely distributed Carnivoran in history that received no help from humans was the lion. There were once lions all over Africa, all over Eurasia, all over North America, and part of South America. No other Carnivoran species-- and all these lions have recently been confirmed to be a single species, which includes modern lions-- has ever had a range like that.

  4. You do have a very good point, but my source described them as the most widely distributed. Do you have a source for the domestic cat?

  5. I can't find a source, but think about it:

    Cats are found in places where there are no foxes or even domestic dogs. Their population "in the wild" in the US is probably equal to that of those that are kept as pets. There are no red foxes on islands in the sub-antarctic.

    They are almost as widespread as a brown rats are.

  6. Again, I agree that you have a very good point, but I would feel more comfortable if we could find some distribution maps.