Natural History

From The Telegraph:

The male fox weighed two stone or 26.5lb and was four foot long, about the height of a seven-year-old child.

The giant fox was captured and killed in Maidstone after a cat in the local neighbourhood was killed.

It was trapped in a cage and put down in a humane way by Keith Talbot, a local vet.

He said foxes had been seen around his parents house days after their 19-year-old tabby cat was found killed on the doorstep.

Zoologists and experts said foxes said foxes could be growing bigger because of ‘easy pickings’ of food scraps in dust bins or even left out by animal lovers.

A dog fox will often grow bigger than the rest of the pack because the social system means the alpha male gets most of the food and the rest get leftovers.

There are thought to be at least 34,000 urban foxes in Britain.

Recently there has been concerns the animals could pose a threat after twins Isabella and Lola Kouparis were attacked in their beds in London.

However animal rights campaigners point out that most foxes live on insects and small mammals and pose no harm to humans unless they are frightened.

The Field Sports Channel is offering £100 for the best story of the largest fox. One taker has come forward with claims he shot a fox weighting 34lb in 2009, although this has not been confirmed with photographic evidence.

I guess the English have adopted one of our customs. In the US, there are coyote killing competitions. In the West, these competitions are about seeing who can kill the most coyotes within a given amount of time. In the East, where big coyotes are legendary, the goal is to see who can kill the biggest one. Anyone who kills a black, white, or otherwise unusually colored individual also gets plaudits. (Remember, the ones in the East have some wolf ancestry.)

Another reason why these foxes could be getting larger is that they have virtually no predation. Wolves no longer exist in England, and fox hunting has been banned. That means that foxes now exist at higher densities than they once did, and it may be that foxes that are bigger and tougher are better at competing for both vixens and food resources than smaller ones. With all of these foxes living in relative proximity to each other, it may be that a dog fox that has some size advantage might be better able to spread his genes, simply by muscling his way around smaller individuals.

And access to food would also play a role.  These foxes now have the nutrition to reach larger sizes.

The fact that this fox was killed in town means that he likely had access to really good nutrition his entire life. His ancestors may have been working their way towards the larger size as I describe may become possible when foxes exist at high densities.

Red foxes do vary quite a bit in size. A 26 to 34 pound fox is much larger than any fox around here. It actually would put  them in the same class as the smallest of coyote bitches.

Now, I’ve never seen one in North America of this size, but I did see one last week.

It was a taxidermied specimen at the German Hunting and Fishing Museum (Deutsches Jagd- und Fischereimuseum). I was shocked at how large this fox was. It was the size of a beagle.

Where I live, red and gray foxes are about the same size– 8-12 pounds. Virtually all red foxes here are derived from English imports to Maryland and Virginia in the seventeenth and eighteenth centuries. Genetically and morphologically, they are almost exactly the same as those foxes in England. Of course, there was a small native population of red foxes that lived in what is now the eastern US, but they were not that common before European settlement. (However, they did exist in Virginia during the Pleistocene).

The ones here also have very distinct black legs, which this particular fox does not have. Only its feet are black.

With 45 different subspecies of red fox,  we should see lots of variance between them. Not only do they come in several distinct phases in the wild, they also vary quite a bit in terms of size.

As wild dogs go, they are the true inheritors of the wolf’s empire. They are now more widely distributed than any other wild carnivore. Not only do they still maintain a vast Holarctic range, that also includes the Nile Valley, they are also found in Australia. Like wolves, they have the ability to rapidly respond to selective pressures and change their morphology and behavior to fit new ecosystems and new niches.

Large size may be of some advantage for certain populations, and that is probably the main reason why giant foxes are starting to appear in different European countries.

But if that readily available food supply disappears and the foxes find themselves suffering from both competition and predation from other animals, the large size may not be quite so advantageous.