Did you know that foxes in the Scottish uplands tend to be larger than the rest of the UK? Most foxes weigh between 12-15lbs and the largest fox ever recorded – found in the Scottish Highlands, weighed a whopping 26lbs!

In Charles Darwin’s Natural Selection it says the following,

“Mr Colquhoun a very good observer wrote that one can distinguish this animal even at a distance from the small fox of the low grounds; he stands higher, his head broad, nose not so pointed, his coat more shaggy and mixed with white hairs: he is much more powerful and preys on young sheep and rears his young, not in holes, but in clefts in the rocks; is less nocturnal in his habits and altogether more like a wolf than a lowland fox.”

This ‘Highland’ or ‘Mountain’ Fox is more closely matched to the Scandinavian fox in size and some have suggested they’re descendants of stock imported from the continent. So why are upland foxes larger than lowland foxes? In higher latitudes like Scotland and Scandinavia we have long winter nights (foxes are primarily nocturnal), allowing a longer hunting period. If a fox can hunt more they will inevitably catch more and thus grow larger.

The increased day length may also help the fox because of increased primary productivity (plant growth). Thinking back to the food pyramid – lots of plants feeds lots of small mammals and mountain hare which in turn feeds the fox. Larger foxes are also better adapted to living in harsher conditions. A larger body loses heat less quickly than a smaller one, which helps in cold environments. And longer legs can help them get through all that snow! This all leads back to Charles Darwin and the survival of the fittest. Only the larger foxes will survive and breed to produce the next generation!

We see foxes occasionally at the Falls of Clyde, last year I was lucky enough to see a vixen and three cubs on a badger watch. I often see signs on the reserve but I never thought they were an upland species until I saw tracks in the snow at the weekend whilst walking up Meall Ghaordaidh, near Killin. Sadly I didn’t see the fox, I was probably too busy huffing and puffing my way up the mountain to notice but as you can see – the print is very fresh so I must have just missed it.

Laura Preston – Scottish Wildlife Trust, Falls of Clyde Ranger
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