The Hidden World of the Fox. Adele Brand
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has shown that the daily wanderings of a territory-owning fox fall into two distinct types. The first is a circumnavigation of its entire territory, and the second – and more common – is of visits to different parts of their range each night. Varying their journeys gives them the optimum chance of exploiting food resources; if they were to concentrate on the same field month upon month, it would eventually run dry of voles while the untapped pasture half a mile away is awash with them. It is worth adding that the enormous bounty provided by people who feed garden foxes has added a third trend: foxes who travel little and appear in sizeable numbers in specific sites every day.
Under more natural conditions, foxes tend to cross the landscape in a large-scale zigzag pattern. They are often religiously loyal to specific routes, wearing narrow paths into grass through repeated trampling. In the wilderness, they climb onto fallen tree trunks and walk down their full length as a kind of elevated track; in Britain, they occasionally exploit railway lines instead. Last year, I was shown some startling footage of a fox in Wales trotting briskly down a train rail hardly wider than a human hand, balancing like an expert on a tightrope.
Railways and foxes often occupy the same sentence. While human commuters frequently feel that our rail network is more of a hindrance than a help to travelling, it is commonly stated that our vulpine neighbours are transported by them. Not as passengers – although there are several credible accounts of urban foxes jumping on board public transport – but rather as walkers along the banks. Even at those moments when the Gatwick Express thunders past the East Croydon congestion at 100 mph, and on just the other side of Network Rail’s perimeter fence, millions of people shop, argue and check their phones, the embankments themselves remain one of the least disturbed environments in the city. It is often said that foxes first immigrated to London in the 1930s, the pioneers moving down railway lines into this new brave world full of human creatures.
But when talking of the arrival of fox in city, it is as well to remember that city has also travelled extensively into the traditional land of the fox. London has bloated massively over the last two centuries, and despite the best efforts of greenbelt campaigners, continues to do so. Many of today’s ‘urban’ foxes may be descended from ‘rural’ foxes whose habitat was suddenly turned into housing estates. Incidentally, records of foxes near towns in Finland date back to the medieval era, and their distinctive barks were heard in Tokyo in the ninth century. There is even some suggestion that foxes scavenged on abandoned scraps from humans as long ago as the Palaeolithic – the Old Stone Age.
Regardless, considerable research has taken place in recent years to establish the impact of railway lines on fox densities and movement patterns. But evidence that dispersing foxes, and indeed territory-owners on the hunt, are funnelled by the railways is also remarkably scant; radio-collared foxes have shown little preference for the train lines.
Taking the wider view, why would they? Humanity has proved tragically skilful in fragmenting the habitat of hedgehogs, toads and dormice, but foxes are much more capable travellers. They can and do cross roads, car parks and fences. Even the natural world’s topography has little impact; genetic sampling from Croatia has shown that they migrate freely across rivers and small mountains.
When not travelling or feeding, foxes require a suitable place to rest. This may be anywhere within their home range, even close to the territorial border. Foxes have more than one den, including sites that may only be used temporarily. Researchers in Polish farmland found that earths tended to be dug on steep south-facing slopes, with western exposure avoided, possibly due to the prevailing westerly winds. In suburban Britain, foxes often rest on greenhouse roofs or sunbathe in quiet alleys. I’ve found one stretched out contentedly on warm plastic in a narrow gap between a wall and a garage, peaceful and safe, despite being within metres of a major supermarket car park used by hundreds of humans each day.
BUT THE STRAND is crossed by thousands upon tens of thousands of people. Even at midnight, it is alive: lights on the arching stonework, music thumping from cars as they choke in bus-filled traffic jams. I’ve come back here because I want to better understand the miracle of foxes in a desert of towering grey rock. Friday night has spilled people upon the streets, shouting, selfie-taking, watching buskers batter their drums. More of them sprawl between the paws of the giant lions of Trafalgar, strangely drawn to the cold stone models of wild animals. Night itself seems defeated by the battle squadron of lights jumping upon these grandest of buildings, reflecting on the river, luring punters into shops. So it continues on the journey southwards: shuttered shops, drunken youths, urban cries and urban dreams.
There is a fox.
A male, all long limbs and thick brush, sits on a patch of grass under one of Brixton’s tower blocks, half illuminated by streetlight. He turns his head towards the car as we pass, watching, just like his kin in the silent and utterly wild Thar Desert.
Adaptability.
That, in essence, is the fox’s gift.
The world is full of magic things, patiently waiting for our senses to grow sharper.
W. B. YEATS
IN A LONELY ARABLE FIELD in eastern Surrey, the North Downs Way National Trail and the Prime Meridian collide in a crossroads perfectly aligned to the points of the compass. To the south lies the ceaseless rumble of the M25 and its luxurious trim of rolling green countryside. Northwards rises the chalky ridge of the Downs – due north, in fact, and I know this from my map and the position of the sun. But if I were a fox, my navigation might be written into my physical senses.
Slightly offset from true north, the Earth’s magnetic north pole drifts each year due to the behaviour of molten iron in the planet’s outer core. The invisible magnetic field that envelops our planet protects us from harmful cosmic rays while also playing host to the geomagnetic storms that produce spectacular auroras: the northern and southern lights. It has had a profound impact on human history, because compasses – those aids to explorers, traders and armies for millennia – only work because their magnets swing to the poles, where the field’s inclination is vertical.
The geomagnetic field and its poles also have very real significance for animal behaviour. Birds may navigate by it, rats become more restless during magnetic storms, and some researchers have argued that resting cows tend to align themselves pointing poleward, except under power cables which locally disrupt the field.
And foxes, perhaps, hunt by it.
Imagine that you need to catch a rodent in dense cover. The rodent, naturally, does not want to be caught, and is equipped with formidable defensive senses of its own. It may also have awkward behaviours; bank voles, for example, reduce their activity upon detecting fox scent, for the rustles of their feet on vegetation are, perhaps aptly, their Achilles heel. But hearing may not be the fox’s only means of pinpointing its target.
A fox that is stealthily approaching its intended meal will be most successful if it orientates itself either within about 20 degrees of the magnetic north, or due south, at least according to one recent study. Leaps from other directions usually fail to pin the prey. If foxes are indeed capable of magnetoreception, the mechanism by which they perceive the direction of the magnetic poles is unclear. The authors of this study speculate that foxes perceive the geometric field as an area of light or shade in their vision – in fact, even in people, laboratory tests show that the field impacts light perception.
Foxes may use the directional information from the magnetic field together with auditory input from the vole’s rustling to move to a fixed distance from the target, allowing a precise leap. If so, foxes are the first species known to use the magnetic field as a measure of distance.
THE PHYSICAL FOX – the frame that supports this curious, intelligent, beguilingly strange canid lifeform – is